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How to virishuvati rivnyannya with the module and the root. Alignment with the module - to take the maximum on EDI s of mathematics (2020). Modulus of number - designation, designation and application

We do not choose mathematics their profession, and they choose us.

Russian mathematician Yu.I. Manin

Alignment with the module

The most collapsible task of school mathematics is equal, which is to avenge the changes under the sign of the module. For a successful expansion of such equals, it is necessary to know the significance of the main authority of the module. It is natural that the learners are responsible for the rozvyazannya of this type.

Basic concepts and power

Modulus (absolute value) of the decimal number be appointed and is displayed like this:

Before the simple powers of the module, the following expressions can be seen:

Significantly what other two powers are fair for any double step.

Krіm moreover, yakscho, de, then i

More foldable module power, yakі can be effectively wicked with vyvіshennі іvnіan іz modules, formulated after the help of the coming theorems:

Theorem 1.For any analytic functionsі unevenness is fair

Theorem 2. Jealousy is stronger than nervousness.

Theorem 3. Equity equal to nervousness.

Let's look at typical examples of tasks on the topic "Rivnyannya, what to avenge the change under the sign of the module.

Razvyazannya rivnyan іz module

We will expand the most in school mathematics by the method, bases on the development of modules. This method is universal, however, in the case of an infamous yogi, zastosuvannya can lead to cumbersome charges. At zvyazku z tsim uchnі povinnі nobility and іnshі, Nayefektivnіshі method and priyomi rozvyazannya such equals. Zokrema, necessary, hover at these stats.

example 1. Rozvyazati rivnyannya. (one)

Solution. Rivnyannia (1) using the "classic" method - the method of unlocking modules. For whom rozіb'єmo numeric everything dots and at the interval that we can look at three falls.

1. Yakshcho, then, , and equal (1) look at the sight. Sounds are screaming. However, here, the meaning is not known to be the root of the equal (1).

2. Yakscho, then equal (1) is acceptable or .

Oscilki, then the root of the river (1).

3. Yakscho, then equal (1) looks like or . Let's see, what.

Suggestion: , .

In case of violation of advancing ranks with the module, actively win the power of the modules with a method of increasing the effectiveness of the development of similar ranks.

butt 2. Rozvyazati rivnyannia.

Solution. So yak i, then the equanimity screams. Into whomever, , , and equal swells at a glance. Zvіdsi otrimuєmo. Prote, there are no roots for that.

Vidpovid: no root.

Example 3. Rozvyazati rivnyannia.

Solution. Bo, then. Yakscho something, and equal swells at a glance.

We take it.

Example 4. Rozvyazati rivnyannia.

Solution.Let's rewrite the equal of an equal-strength looker. (2)

Otrimane equals to equal to type.

Taking Theorem 2 to heart, one can assert that equal (2) is more equal than unevenness. We take it.

Suggestion: .

Example 5. Rozvyazati rivnyannya.

Solution. Tse equal may look. Tom, consistent up to Theorem 3, there may be nerivnist or .

Example 6. Rozvyazati rivnyannia.

Solution. Let's say what. So yak, then the task of alignment looks like a square alignment, (3)

de . Oskіlki rivnyannya (3) may have a single positive root and then . We need to take two roots of outward alignment: that .

Example 7. Rozvyazati rivnyannia. (4)

Solution. Oskіlki rivnyanniaequal to the marriage of two equals:і , then with the perfect alignment (4) it is necessary to look at two upside downs.

1. Yakscho, then chi.

Zvіdsi otrimuemo, that.

2. Yakscho, abo.

Bo, then.

Suggestion: , , , .

Example 8.Rozvyazati rivnyannia . (5)

Solution. Oskіlki i, then. Zvіdsi i z rіvnyannya (5) vyplivaє, like i, tobto. here maєmo system rivnyan

However, the system is equal and inconsequential.

Vidpovid: no root.

Example 9. Rozvyazati rivnyannia. (6)

Solution. How to know, then that equal (6) is acceptable

Abo. (7)

Oskіlki rіvnyannya (7) may look, tse rіvnyannya rіvnostrіvno nerіvnіnі. We take it. So yak, then chi.

Suggestion: .

butt 10Rozvyazati rivnyannia. (8)

Solution.Similar to Theorem 1, one can write

(9)

Take the jealousy to the point of respect (8), timidly wisps from the one who offends the nervousness (9) turns to the point of jealousy, tobto. maє mіsce system rіvnyan

However, after Theorem 3, a system of equalities is induced even stronger than a system of irregularities

(10)

Breaking the system of irregularities (10) is acceptable. If the system of irregularities (10) is more equal (8), then there is no single root.

Suggestion: .

Example 11. Rozvyazati rivnyannia. (11)

Solution. Let's go and then equalize (11) vyplyvaє equaly.

Sounds screaming, sho. In this rank, there may be a system of irregularities

Razvyazannym given a system of irregularities є that .

Suggestion: , .

butt 12Rozvyazati rivnyannia. (12)

Solution. Rivnyannia (12) vyrishuvatememo by the method of sequential unlocking of modules. For whom we can look at a sprat of vipadkiv.

1. Yakscho, then.

1.1. Yakscho , then , .

1.2. Yakscho something. Prote, to that, the razі rivnyannya (12) has no roots.

2. Yakscho, then.

2.1. Yakscho , then , .

2.2. Yakscho, then th.

Suggestion: , , , , .

butt 13Rozvyazati rivnyannia. (13)

Solution. Shards of the left part of the river (13) are not visible, then i . At zvyazku z tsim, i rivnyanya (13)

nabuvaє vyglyadu abo.

Looks like it's equal equal to the marriage of two equalsі , virishuyuchi yakі otrimuemo, . So yak, then equal (13) may have one root.

Suggestion: .

Example 14. Unleash the rivnyan system (14)

Solution. Oskilki i , i . Also, from the system of equals (14) we take some of the systems of equals:

The root of the guidance system is equal to the roots of the equal system (14).

Suggestion: , , , , , , , .

Example 15. Unleash the rivnyan system (15)

Solution. Bo, then. For each link from the equalization system (15), two equalization systems are taken

The roots of the first system are equal є і, and that is the same as the other system equals і.

Suggestion: , , , .

Example 16. Unleash the rivnyan system (16)

Solution. From the first level of the system (16) we see that .

Oscilki, then . Let's take a look at another level of the system. Oskilki, then , and equal swells at a glance, , or .

How to suggest valuesat the first level of the system (16), then either .

Suggestion: , .

For more in-depth development of methods for solving problems, pov'yazanih іz rozvyazkom ryvnyan, what to do to change the change under the sign of the module, you can get the reference books from the list of literature that are recommended.

1. Collection of problems in mathematics for university students / Ed. M.I. Scanavi. - M.: Mir i Osvita, 2013. - 608 p.

2. Suprun V.P. Mathematics for high school students: task of advanced folding. - M: KD "Librocom" / URSS, 2017. - 200 p.

3. Suprun V.P. Mathematics for high school students: non-standard methods for solving problems. - M: KD "Librokom" / URSS, 2017. - 296 p.

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MBOU ZOSh No. 17 m. Ivanova

« Rivnyannya with the module "
Methodical development

Stocked

teacher of mathematics

Lebedeva N.V.

20010

Explanatory note

Section 1. Intro

Section 2. Main Powers Section 3. Geometric interpretation of the concept of the modulus of a number Section 4. Graph of the function y = | Section 5. Mental cognition

Part 2

Razdіl 1.Rivnyannya mind | F(x) | = m (easiest) Section 2. Equal to the form F(|х|) = m Section 3. Equal to the mind | F(x) | = G(x) Section 4. Equal to mind | F(x) | = ± F(x) (beautiful) Section 5. Equal to the mind | F(x) | = | G(x) | Rozdіl 6. Apply the tie of non-standard rivn Section 7. Equal to the mind | F(x) | + | G(x) | = 0 Section 8. Equal to the mind | a 1 x ± 1 | ± |a 2 x ± 2 | ± …|a n x ± y n | = m Section 9

Chapter 3

Section 1. Trigonometric alignment Partition 2. Showing the alignment Section 3. Logarithmic Equation Section 4. Irrational alignment Section 5. Order for the promotion of folding Vidpovidі to the right List of references

Explanatory note.

The concept of the absolute value (modulus) of a decimal number is one of the essences of its characteristics. Tse understanding may have become very wide in various branches of the physical, mathematical and technical sciences. In practice, for the course of mathematics in secondary school, up to the Program of the Ministry of Defense of the Russian Federation, the understanding of the “absolute value of a number” is noted repeatedly: in the 6th grade, the designation of the module is introduced, its geometrical zmist; in the 8th class, the understanding of the absolute error is formed; in the 11th class, the understanding is heard in the division “Korin nth step." Dosvіd vykladannya pokaєє, shcho uchnі often stikayutsya z difficulties pіd hіvіshennya zavdan, scho vmagayut knowledge of the given material, and often miss, without proceeding to vikonannya. The texts of examination tasks for the course of the 9th and 11th grades also include similar tasks. In addition, moreover, if you present to the graduates of the schools of the VNZ, they are rehabilitated, and, for the most part, even less than the school program. For life in the future, it is even more important to mold the mathematical style of thought, which manifests itself in the singing of Rozum's newcomers. In the process of executing the task of the modules, it is necessary to zastosovuvat such a decision, as a further specification, analysis, classification and systematization, analogy. The versatility of similar tasks allows you to reconsider the knowledge of the main divisions of the school course, the riven of logical thought, and the beginnings of the basic activity. Tsya robot is assigned to one of the divisions - the virishennya rivnyan, scho to avenge the module. The won is made up of three divisions. In the first division, the main concepts and the most important theoretical concepts are introduced. At the other, nine main types of equalizations are shown, to avenge the module, methods of their perfection are looked at, butts of different equalities of folding are picked up. The third one has folding and non-standard alignment (trigonometric, display, logarithmic and irrational). Up to the dermal type, it is right for an independent variant (various indications and instructions are given). The main purpose of this work is to provide methodical assistance to students in preparation for lessons and in the organization of optional courses. The material can also be used as a heading guide for high school students. The manager, encouraged in work, cica and don’t start simple at the top, which allows you to increase the initial motivation of the students more aware, change your health, improve the training of graduate students to the entrance to the VNZ. Differentiation of the right to proponate the right to transfer the transition from the reproductive level to the material to the creative one, and to inspire the ability to learn to develop one’s knowledge of the hour of accomplishment of non-standard tasks.

Section 1. Intro.

Section 1. Appointment of the absolute value .

Appointment : The absolute value (modulus) of a decimal number a called an unknown number: a or -BUT. Designation: a The entry reads like this: “the modulus of the number a” or “the absolute value of the number a”

and if a > 0

a│ = │ 0, so a = 0 (1)

- a, like a
Apply: 1) │2,5│ = 2,5 2) │-7│ = 7 3) │1 - √2│ = √2 – 1
    Expand Virazu module:
a) │x - 8│, if x > 12 b) │2x + 3│, if x ≤ -2 │x - 8│= x - 8 │ 2x + 3│= - 2x - 3

Section 2. Main characteristics.

Let's take a look at the main power of absolute magnitude. Power #1: Protilezhnі number mayut equal modules, tobto. │а│=│-а│ Let's show the fidelity of jealousy. Let's write down the number - a : │- a│= (2) Equal marriages (1) and (2). It is obvious that the designation of the absolute values ​​of numbers aі - a run away. Otzhe, │а│=│-а│
When looking at the advancing authorities, we mix in their formulas, so that their proof can be found in Power #2: The absolute value of the sum of the final number of actual numbers does not exceed the sum of the absolute values ​​of the additional numbers: Power #3: The absolute value of the difference between two real numbers does not exceed the sum of their absolute values: │а - в│ ≤│а│+│в│ Power #4: The absolute value of the creation of the end number of the real numbers is more important for the completion of the absolute values ​​of the multipliers: Power #5: The absolute value of the part of the real numbers is equal to the private one of their absolute values:

Section 3. Geometrical interpretation of the concept of the modulus of a number.

You can put a point on the numerical line for the skin number, as if it were a geometric image of the number. The skin dot on the numerical straight line shows you to the cob for the sake of it. dozhina vіdіzka vіd vіdlіku vіdlіku to tsієї point. Tsya vіdstan priymaєtsya zavzhd as a non-negative value. To this end, the dozhina of a double wedge will be a geometric interpretation of the absolute value of the current number.

A geometric illustration was given, confirming the accuracy of No. 1, tobto. modules of opposite numbers are equal. It is easy to understand the justice of equality: │x - a│= │a - x│. It is also more obvious that the solution is equal │х│= m, de m ≥ 0, and x 1.2 itself = ± m. Apply: 1) │х│= 4 x 1.2 = ± 4 2) │х - 3│= 1
x 1.2 = 2; 4

Section 4. Graph of the function y = │х│

The scope of the function is all actual numbers.

Rozdіl 5. Smart cognition.

Nadal, when looking at the butts of the rose, the rivnyan will be vikoristan such a clever designation: ( - sign of system [ - sign of marriage When the system of equalities (irregularities) is rozvyazanny, there is a gap between the solutions to enter the system of equalities (irregularities). When the marriage of rivnyan (irregularities) is broken, there is a general decision that enters to the marriage of rivnyan (irregularities).

Chapter 2

For whom we have divided, we can look at ways of developing algebra equal, which can be done with one or more module.

Section 1. Equal to the mind │F(х)│= m

Rivnyanna tsgogo mind is called the simplest. There may be a solution even and only if m ≥ 0. For the purpose of the module, the difference is equal to the combination of two equals: │ F(x)│=m
Apply:
1. Untie equalization: │7х - 2│= 9


Suggestion: x 1 = - 1; X 2 = 1 4 / 7 2
│x 2 + 3x + 1│= 1

x 2 + 3x + 2 = 0 x 2 + 3x = 0 x 1 = -1; x 2 \u003d -2 x (x + 3) \u003d 0 x 1 \u003d 0; x 2 = -3 Vidpovid: the sum of the roots is dorіvnyu - 2.3
│x 4 -5x 2 + 2│= 2 x 4 - 5x 2 = 0 x 4 - 5x 2 + 4 = 0 x 2 (x 2 - 5) = 0 significant x 2 = m, m ≥ 0 x = 0 ; ±√5 m 2 – 5m + 4 = 0 m = 1; 4 - offensive values ​​satisfy the mind m ≥ 0 x 2 = 1 x 2 = 4 x = ± 1 x = ± 2 Verdict: number of roots of rivers 7. Right:
1. Razv'yazhit rivnyannya and show the sum of roots: │х - 5 │ = 3 2 . Expand the equation and show the smaller root: │х 2 + х│ = 0 3 . Razv'yazhit rivnyannya and show the greater root: │x 2 - 5x + 4 │ \u003d 4 4 .Rіshіt rіvnyannya i vkazhіt qіliy korіn: │2х 2 – 7х + 6│= 1 5 .Rіshіt rіvnyannya i vkazhіt kіlkіst korіnіv: │х 4 – 13х 2 + 50│= 14

Section 2. Equal to the mind F(│х│) = m

The argument of the function in the left part is changed under the sign of the module, and the rights of the part are in the change. Let's take a look at two ways of rozv'yazannya rіvnyan this kind. 1 way: According to the absolute value, the difference is equal to the combination of the two systems. In the skin of these, the mind submodular viraz is superimposed. F(│х│) =m
Since the function F(│х│) is paired for the entire range of assignment, then the root equals F(х) = m і F(-х) = m are pairs of opposite numbers. Therefore, to complete one of the systems (when looking at the applications in the indicated way, one system will be solved). 2 way: Zastosuvannya method of zaprovadzhennya new zminnoy. With this, the value │х│= a de a ≥ 0 is introduced.
Apply: 1 . Razv'yazhit rivnyannya: 3x 2 - 4│х│= - 1 We'll speed up the introduction of a new change. Significantly │х│= a, de a ≥ 0. Removal of alignment 3a 2 - 4a + 1 \u003d 0 D \u003d 16 - 12 \u003d 4 a 1 \u003d 1 a 2 \u003d 1/3 │х│= 1/3. The skin has two roots. Suggestion: x 1 = 1; X 2 = - 1; X 3 = 1 / 3 ; X 4 = - 1 / 3 . 2. Untie equal: 5x 2 + 3│x│- 1 \u003d 1 / 2 │x│ + 3x 2
We know the solution to the first marriage system: 4x 2 + 5x - 2 \u003d 0 D \u003d 57 x 1 \u003d -5 + √57 / 8 x 2 \u003d -5-√57 / 8 Dearly, that x 2 does not satisfy the mind x ≥ 0. Solutions another system will be a number that is proportional to x 1 . Suggestion: x 1 = -5+√57 / 8 ; X 2 = 5-√57 / 8 .3 . Rise equal: х 4 – │х│= 0 Significantly │х│= a, de a ≥ 0. Take equal a 4 – a = 0 a (a 3 – 1) = 0 a 1 = 0 a 2 = 1 Turn to the reverse change: │х│=0 and │х│= 1 x = 0; ± 1 Suggestion: x 1 = 0; X 2 = 1; X 3 = - 1.
Right: 6. Razv'yazhit rivnyannya: 2│х│ - 4.5 = 5 - 3/8 │х│ 7 . Razv'yazhit rivnyannya, at vіdpovіdі indicate the number of roots: 3х 2 - 7│х│ + 2 = 0 8 . Razv'yazhіt rivnyannya, at vіdpovіdі vkazhіt qіlі solution: х 4 + │х│ - 2 = 0

Section 3. Equal to the mind │F(х)│ = G(х)

The rights of a part of a given species to lie in change and, therefore, it can be solved even and less so, if the rights of a part of the function G (x) ≥ 0. A part of the equal can be found in two ways: 1 way: Standard, based on the development of the module, vyhodyachi z yogo appointment and polagaє in an equal transition to the combination of two systems. │ F(x)│ =G(X)

Denmark is able to rationally twist at times folding for the function G (x) and less folding - for the function F (x), so the variance of irregularities is transferred to the function F (x). 2 way: Perebuvayut at the transition to an equally strong system, at the same time the right part of the mind is superimposed. │ F(x)│= G(x)

The Danish way of stowing is more efficient, which means that for the function G(x) there is less folding, lower for the function F(x), so that the breakdown of unevenness G(x) ≥ 0 is transferred. option. Apply: 1. Untie equalization: │x + 2│= 6 -2x
(1 way) Verify: x = 1 1 / 3 2.
│x 2 - 2x - 1 │ \u003d 2 (x + 1)
(2 way) Verdict: Tver root - 3.
3. Rozv'yazhіt rivnyannya, at vіdpovіdі show the sum of roots:
│x - 6 │ \u003d x 2 - 5x + 9

Verdict: the sum of the roots is good 4.
Right: 9. │x + 4│= - 3x 10. Razv'yazhіt rivnyannya, at vіdpovіdі specify the number of rozv'yazkіv: │х 2 + х - 1│= 2х - 1 11 . Razv'yazhіt rivnyannya, vіdpovіdі vkazhіt dobutok root: │x + 3│= x 2 + x - 6

Section 4. Equal to the mind │F(x)│= F(x) and │F(x)│= - F(x)

Rivnyannya tsgogo mind is sometimes called "beautiful". Shards of the right of a part of the equal to lie in the form of a change, the decision is to be made and the same, if the right of the part is non-negative. Therefore, vihіdnі іvnіnіnі іvnіnіnі іvnosіlnі nerіvnosti:
│F(x)│= F(x) F(x) ≥ 0 and │F(x)│= - F(x) F(x) Apply: 1 . Razv'yazhіt rivnyannya, at vіdpovіdі show a lesser qіliy root: │5x - 3│= 5x - 3 5x - 3 ≥ 0 5x ≥ 3 x ≥ 0.6 Verify: x = 12. Razvyazіt rivnyannya, vіdpovіdі vіdvіdі vkazhіt dovzhіnі promіzh: │х 2 - 9 │= 9 - х 2 х 2 - 9 ≤ 0 (х - 3) (х + 3) ≤ 0 [- 3; 3] Vidpovid: dozhina promizhku dorіvnyuє 6.3 . Splitting is equal, at the same time, enter the number of multiple splits: │2 + x - x 2 │ = 2 + x - x 2 2 + x - x 2 ≥ 0 x 2 - x - 2 ≤ 0 [- 1; 2] Suggestion: 4 whole solutions.4 . Razv'yazhіt rivnyannya, vіdpovіdі vkazhіt the greatest root:
│4 - x -
│= 4 – x –
x 2 - 5x + 5 \u003d 0 D \u003d 5 x 1.2 \u003d
≈ 1,4

Verdict: x = 3.

Right: 12. Razv'yazhіt rivnyannya, at vіdpovіdі vkazhіt qіliy korіn: │х 2 + 6х + 8 │ = x 2 + 6х + 8 13. Razv'yazhіt rivnyannya, y vіdpovіdі specify the number of tіlih solutions: │13x – x 2 - 36│+ x 2 – 13x + 36 = 0 14. Razv'yazhіt rivnyannya, in vіdpovіdі indicate the whole number, which is not the root of іvnyannia:

Section 5. Equal to the mind │F(x)│= │G(x)│

Shards of insulting parts of equal are non-negative, then the solution conveys a view of two vipadkiv: pіdmodulnі virazi vіvnі chi protilezhnі behind the sign. Otzhe, vyhіdne rіvnyannja іvnostrіvnі sukupnі tvoh іvnyan: │ F(x)│= │ G(x)│
Apply: 1. Rozv'yazhіt rivnyannya, vіdpovіdі vkazhіt qіliy korіn: │х + 3│=│2х - 1│
Suggestion: whole root x = 4.2. Untie the river: x - x 2 - 1│ \u003d │2x - 3 - x 2 │
Verdict: x = 2.3 . Rozv'yazhіt rivnyannya, in vіdpovіdі vkazhіt dobutok root:




Roots equal 4x2 + 2x - 1 = 0x1.2 = - 1±√5 / 4 Vidpovid: dobutok korіnnya dorіvnyuє - 0.25. Right: 15 . Razv'yazhіt rivnyannya, at vіdpovіdі vkazhіt tsіle solution: │х 2 – 3х + 2│= │х 2 + 6х - 1│ 16. Rozv'yazhіt rivnyannya, vіdpovіdі vkazhіt less root: │5x - 3│=│7 - x│ 17 . Rozv'yazhіt rivnyannya, at vіdpovіdі show the sum of roots:

Rozdіl 6. Apply the tie of non-standard rivn

We can look at examples of non-standard rivnyans, for example, the absolute value of which depends on the appointments. Apply:

1. Razv'yazhіt rivnyannya, vіdpovіdі vkazhіt sum of roots: х │х│- 5х – 6 = 0
Suggestion: the sum of the roots is 1 2. . Razv'yazhіt rivnyannya, vіdpovіdі vkazhіt lesser root: х 2 - 4х ·
- 5 = 0
Suggestion: smaller root x = - 5. 3. Untie the river:

Verdict: x = -1. Right: 18. Razv'yazhіt equal and show the sum of the roots: x │3x + 5│= 3x 2 + 4x + 3
19. Untie equal: x 2 - 3x \u003d

20. Untie the river:

Section 7. Equal to the mind │F(x)│+│G(x)│=0

It is not important to remember that the left part is equal to the sum of non-negative values. Otzhe, in the future, even if it is possible, then even more, if the offense of the dodanki is equal to zero at once. Rivnyannya equally strong systems equal: │ F(x)│+│ G(x)│=0
Apply: 1 . Untie the river:
Verdict: x = 2. 2. Untie the river: Verify: x = 1. Right: 21. Untie the river: 22 . Rozv'yazhіt rivnyannya, at vіdpovіdі show the sum of roots: 23 . Razv'yazhit rіvnyannya, vіdpovіdі vkazhіt kіlkіst іdіnі:

Section 8. Equal to the mind │а 1 x + y 1 │±│а 2 x + y 2 │± … │а n x + в n │= m

In order to improve the equality of this mind, the method of intervals is used. If you want to check the last of the modules, then take it n collections of systems, which are too cumbersome and unhandy. Let's look at the method of the interval algorithm: 1). Know the meaning of the change X, For any skins, the module is equal to zero (zero pіdmodulnyh vrazіv):
2). Found values ​​in the number line, as divided into intervals (the number of intervals is probably more n+1 ) 3). Significantly, with a certain sign, the skin module is opened to the skin module with a minimum of intervals (when the solution is drawn up, you can choose a numerical straight line, assigning signs to it) 4). Vihіdne rіvnyannya іvnostrіvno sukupnostі n+1 systems, in the skin, among them, the belonging of the change X one of the intervals. Apply: 1 . Razv'yazhіt rivnyannya, vіdpovіdі vkazhіt the greatest root:
one). We know zero submodular viruses: x = 2; x = -3 2). Significantly known values ​​on the number line and significant, with some sign, the skin modulus curves on subintervals:
x – 2 x – 2 x – 2 - - + - 3 2 x 2x + 6 2x + 6 2x + 6 - + + 3)
- there is no solution Rivnyannya may have two roots. Vidpovid: maximum root x = 2. 2. Rozv'yazhіt rivnyannya, at vіdpovіdі vkazhіt qіliy korіn:
one). We know zero submodular viruses: x = 1.5; x = - 1 2). Significantly known value on the number line i is significant, with a certain sign the skin modulus curves on subintervals: x + 1 x + 1 x + 1 - + +
-1 1.5 x 2x - 3 2x - 3 2x - 3 - - +
3).
The rest of the system does not have a solution, then, equal can have two roots. At the beginning of the rozv'yazannya ryvnyannya next turn respect for the "-" sign in front of another module. Suggestion: the whole root x = 7. 3. Razv'yazhit rivnyannya, in vіdpovіdі show the sum of roots: 1). We know zero submodular viruses: х = 5; x = 1; x = - 2 2). Significantly known values ​​on the number line and significant, with a certain sign, the skin modulus curves on sub-intervals: х – 5 х – 5 х – 5 х – 5 - - - +
-2 1 5 x x – 1 x – 1 x – 1 x – 1 - - + + x + 2 x + 2 x + 2 x + 2 - + + +
3).
Equation has two roots x = 0 and 2. Verdict: the sum of the roots is 2. 4 . Razv'yazhit rivnyannya: 1). We know zero submodular viruses: х = 1; x = 2; x = 3. 2). Significantly, with a certain sign, the skin module is taken away from the intervals. 3).
Combined solutions for the first three systems. Suggestion: ; x = 5.
Right: 24. Untie the river:
25. Rozv'yazhіt rivnyannya, at vіdpovіdі show the sum of roots: 26. Rozv'yazhіt rivnyannya, vіdpovіdі vkazhіt lesser root: 27. Rozv'yazhіt rivnyannya, vіdpovіdі vkazhіt greater root:

Section 9

Rivnyannya, scho to avenge a sprinkling of modules, conveys the presence of absolute values ​​in submodular virases. The main principle of the expansion of this type is the following expansion of modules, starting from the old one. At the result, the decision will be made, and the divisions No. 1, No. 3 will be looked at.

Apply: 1. Untie the river:
Vidpovid: х = 1; - eleven. 2. Untie the river:
Vіdpodіd: х = 0; 4; - 4. 3. Rozv'yazhіt rivnyannya, in vіdpovіdі vkazhіt dobutok root:
Vidpovid: dobutok root dorivnyu - 8. 4. Untie the river:
Significantly equal marriage (1) і (2) that perceptible solution of the skin of them is okremo for clarity of design. So, as an insult, it is equal to take more than one module, it is better to make an equal transition to the totality of systems. (1)

(2)


Suggestion:
Right: 36. Razv'yazhіt rivnyannya, at vіdpovіdі vkazhіt sum of roots: 5 │3x-5│ = 25 x 37. Expand the equal, as the root is greater than one, in the case of the root, indicate the sum of the root: │x + 2│ x - 3x - 10 \u003d 1 38. Razvyazіt rivnyannya: 3 │2х -4│ = 9 │х│ 39. Razv'yazhіt rivnyannya, at vіdpovіdі vkazhіt number of roots on: 2 │ sin x │ \u003d √2 40 . Rozv'yazhіt rivnyannya, at vіdpovіdі indicate the number of roots:

Section 3. Logarithmic equalization.

Before unleashing the offensive equalities, it is necessary to repeat the power of logarithms and logarithmic functions. Apply: 1. Expanding the rіvnyannya, vіdpovіdі vіdvіdі vіdkіt dobutok korіnnya: log 2 (х+1) 2 + log 2 │x+1│ = 6 O.D.Z. x+1≠0 x≠ - 1

1 fallow: if x ≥ - 1, then log 2 (x+1) 2 + log 2 (x+1) = 6 log 2 (x+1) 3 = log 2 2 6 (x+1) 3 = 2 6 x+1 = 4 x = 3 – brain-pleasing x ≥ - 1 2 upside down: yes x log 2 (x+1) 2 + log 2 (-x-1) = 6 log 2 (x+1) 2 + log 2 (-(x+1)) = 6 log 2 (-(x+1) 3) = log 2 2 6- (x+1) 3 = 2 6- (x+1) = 4 x = - 5 – satisfied mental x - 1
Vidpovid: dobutok root dorivnyu - 15.
2. Razv'yazhit rivnyannya, at vіdpovіdі show the sum of roots: lg
O.D.Z.



Verdict: the sum of roots is 0.5.
3. Untie the line: log 5
O.D.Z.

Verdict: x = 9. 4. Untie equalization: │2 + log 0.2 x│+ 3 = │1 + log 5 x│ O.D.Z. x > 0 Faster by the formula to the transition to the other basis. │2 - log 5 x│+ 3 = │1 + log 5 x│
│2 - log 5 x│- │1 + log 5 x│= - 3 We know zero submodular viruses: x = 25; x = qi numbers divide the range of admissible values ​​by three intervals, which is equal to the sum of the three systems.
Suggestion: .

Remaining solution the union of the appearances of the okremikh parts:

x (–∞; –3] [–1; + ∞).

Suggestion: x (–∞; –3] [–1; + ∞) .

Rivnyannya mind | = | y |

butt 1(Algebra grade 8). Razv'yazati іz two modules: 2 * |x - 1| + 3 = 9 - | x - 1 |.

Solution:

Suggestion: x 1 = 3; x 2 = 1.

butt 2(Algebra grade 8). Virishiti nerіvnіst:

Solution:

Rivnyannya mind | =y

butt 1(Algebra grade 10). Know x:

Solution:

It is also important to carry out a re-verification of the right part, otherwise you can write at the top of the pardon root. From the system it is clear that it is not possible to lie at the promenade.

Suggestion: x=0.

sumi module

Retail module

The absolute value of the difference between two numbers x that y dorivnyuє vіdstani between points with coordinates Xі Y on the coordinate line.

example 1.

butt 2.

Modulus of a negative number

To know the absolute value of a number, if it is less than zero, it is necessary to recognize it, as far as it is far from zero. Oscilki look forward to positive (it is impossible to go through negative steps, it’s just steps in a different direction), the result is always positive. Tobto,

To put it simply, the absolute value of a negative number may have an opposite value.

Zero module

Houses of power:

Why can't we say that an absolute value is a positive number: zero is neither negative nor positive.

Square module

The module of the square is always more advanced in terms of the square:

Attach graphics from the module

Often in tests and on tests, tasks are written down, yak it is possible to err, having less analyzed the graphs. Let's take a look at this task.

example 1.

Given a function f(x) = |x|. It is necessary to have a schedule for 3 to 3 times a week 1.

Solution:

Explanation: From the little one you can see that the graph is symmetrical along the Y axis.

butt 2. It is necessary to paint the graphs of the functions f(x) = |x–2| and g(x) = |x|–2.

Solution:

Explanation: the constant in the middle of the absolute value moves the entire graph right-handed, as it is negative, and left-hand, as positive. Ale postiyna zvnі peresuvatime graph uphill, which is more positive, i down, which is more negative (yak - 2 at the function g(x)).

Vertex coordinate x(Point, where two lines join, the top of the graph) - the whole number, on the chart, it moves to the left or to the right. A coordinate y- tse value, like the graph zsuvaetsya uphill chi down.

You can use such graphics for the help of online supplements for inspiration. With this help, you can at first wonder how to add constants to functions.

Interval method for tasks from module

The method of intervals is one of the best ways to know the difference in problems with a module, especially in the case of viruses.

To match the method, follow these steps:

  1. Equal skin viraz to zero.
  2. Know the meaning of the change.
  3. Put points on the number line, subtract from point 2.
  4. Signify on the spaces the sign of viraziv (negative or positive value) and paint the symbol - or + vіdpovіdno. The simplest is to assign a sign for the help of the substitution method (substituting whether the value is from the space).
  5. Virishiti nerivnosti z otrimanimi signs.

butt 1. Virishiti path of intervals.

Solution:

One of the most interesting topics for uchnіv is rozvyazannya rivnyan, scho to avenge the change under the sign of the module. Let's take a look at the cob, why is it tied? Why, for example, are square equals more children clattering like peas, and with such far from the best understanding, like a module, can there be more problems?

In my opinion, all the folds are due to the existence of clearly formulated rules for the implementation of the module. So, virishyuyuchi square equal, learners know exactly what it is necessary for you to write down the formula of the discriminant, and then the formula of the root of the square equal. And what about the robit, how about the module being fixed on equal ground? We will try to clearly describe the necessary plan for the time, if it is equal to avenge the unknown under the sign of the module. We will bring a sprat of applications to the skin drop.

Ale for the cob module designation. Father, modulus of number a called the same number, like a I can't see -a, which is the number a less than zero. You can write it like this:

|a| = a if a ≥ 0 and |a| = -a, same as a< 0

Speaking about the geometrical sense of the module, the next thing to remember is that the skin decimal number has a single point on the numerical axis - її to coordinate. So the axis, the module or the absolute value of the number, is called the distance from the center of the point to the cob in the numerical axis. Always be given a positive number. In this order, the modulus of any negative number is positive. Before speech, learn at what stage a lot of learners start to stray. The module may have a number, and the result of the module's input is always a positive number.

Now let's move on without a hitch to the opening of the river.

1. Perspective equal to mind | \u003d s, de s - deisne number. The price can be checked for the help of the module.

All the current numbers are divided into three groups: t, which is greater than zero, t, which is less than zero, and the third group is the whole number 0. Let's write down the solution for the visual scheme:

(±c, if s > 0

Yakscho | x | = c, then x = (0, so c = 0

(no root, yakscho z< 0

1) | = 5, because 5> 0, then x = ±5;

2) | = -5 because -5< 0, то уравнение не имеет корней;

3) | = 0 then x = 0.

2. Equal to mind | f(x) | = b de b > 0. To complete this alignment, you need to get the module. Robimo tse: f(x) = b chi f(x) = -b. Now it is necessary to repair the skin from the otrimanih equals. Yakshcho at the weekend Rivnian b< 0, решений не будет.

1) | x + 2 | = 4, because 4 > 0, then

x + 2 = 4 or x + 2 = -4

2) | x 2 - 5 | = 11, because 11 > 0, then

x 2 - 5 = 11 or x 2 - 5 = -11

x 2 = 16 x 2 = -6

x = ± 4 no root

3) | x 2 - 5x | = -8, because -eight< 0, то уравнение не имеет корней.

3. Rivnyannya mind | f(x) | = g(x). For the replacement of the module, such a solution is equal to the mother, for example, part of the law is greater than zero, tobto. g(x) ≥ 0. Then we can calculate:

f(x) = g(x) or f(x) = -g(x).

1) | 2x - 1 | \u003d 5x - 10. The cost of matima is the root, yakscho 5x - 10 ≥ 0. The very beginning of the rozvyazannya of such rivnas.

1. O.D.Z. 5x – 10 ≥ 0

2. Solutions:

2x - 1 = 5x - 10 or 2x - 1 = - (5x - 10)

3. Combined O.D.Z. that decision, we take:

Root x = 11/7 is not suitable for O.D.Z., vin is less than 2, and x = 3 is your mind's satisfaction.

Suggestion: x = 3

2) | x - 1 | = 1 - x 2.

1. O.D.Z. 1 – x 2 ≥ 0

(1 – x)(1 + x) ≥ 0

2. Solutions:

x - 1 = 1 - x 2 or x - 1 = - (1 - x 2)

x 2 + x - 2 = 0 x 2 - x = 0

x = -2 or x = 1 x = 0 or x = 1

3. Joint decision and O.D.Z.:

More than a root is suitable x = 1 and x = 0.

Suggestion: x=0, x=1.

4. Equal to mind | f(x) | = | g(x)|. This is equal to two upcoming equals f(x) = g(x) or f(x) = -g(x).

1) | x 2 - 5x + 7 | = | 2x - 5 |. Tse equal equal to two will come:

x 2 - 5x + 7 = 2x - 5 or x 2 - 5x +7 = -2x + 5

x 2 - 7x + 12 = 0 x 2 - 3x + 2 = 0

x = 3 or x = 4 x = 2 or x = 1

Suggestion: x = 1, x = 2, x = 3, x = 4.

5. Rivnyannya, yakі vyrіshuyusya way of substitution (replace change). The Danish solution method is easiest to explain on a specific application. So, let's give a square equal to the module:

x 2 – 6|x| + 5 = 0. For the quality of the module x 2 = |x| 2 , that can be rewritten like this:

|x| 2 - 6 | x | + 5 = 0. Let's change | = t ≥ 0, then math:

t 2 - 6t + 5 \u003d 0. Considering the given equal, we assume that t \u003d 1 or t \u003d 5. Let's turn to replace:

|x| = 1 chi |x| = 5

x = ±1 x = ±5

Suggestion: x=-5, x=-1, x=1, x=5.

Let's look at another example:

x 2 + | – 2 = 0. For module quality x 2 = |x| 2 , to

|x| 2+ |x| - 2 = 0. Let's change | x | = t ≥ 0 then i:

t 2 + t - 2 \u003d 0. Virishingly given equal, it is acceptable, t \u003d -2 or t \u003d 1. Let's turn to replace:

|x| = -2 chi |x| = 1

No root x = ± 1

Suggestion: x=-1, x=1.

6. Another type of alignment is alignment with a "foldable" module. Up to such equalities one can see the equalization, in which there are modules in modules. Rivnyannya tsgogo mind can be violated, blocking the power of the module.

1) |3 – |x|| \u003d 4. D_yatimemo is the same, like in equals of another type. Because 4 > 0, then we take two equalities:

3 - | x | = 4 chi 3 – |x| = -4.

Now virazimo at the skin level module x, todi | = -1 chi |x| = 7.

Virishuemo skin from otrimanih equal. The first equal does not have a root, because -one< 0, а во втором x = ±7.

Verify x=-7, x=7.

2) | 3 + | x + 1 | | = 5

3 + | x + 1 | = 5 chi 3 + |x + 1| = -5

|x + 1| = 2 | x + 1 | = -8

x + 1 = 2 or x + 1 = -2. There is no root.

Suggestion: x=-3, x=1.

Іsnuє shchey and universal method of rozv'yazannya іvnyan іz module. Tse method of intervals. Ale mi yogo looked at.

blog.website, with a new or private copy of the material sent on the original binding.

The module is one of those silent speeches, about all the chules, but in truth, nobody normally understands. To this day there will be a great lesson, assignments to the top of the line from the modules.

I’ll tell you right away: the lesson will be awkward. І vzagalі modules vzagalі topic is notably clumsy. “So, obviously, awkward! My brain is growing! - to say a lot of learning, but all the brains are explored through those that most people have no knowledge at the head, but like crap. The first lesson is to turn crap into knowledge.

Trochy theory

So let's go. Let's start with the most important thing: what is a module? I'll guess that the modulus of the number is just the same number, but take it without the minus sign. Tobto, for example, $ \ left | -5 \right | = $5. Abo $\left | -129.5\right | = $129.5.

Is everything simple? Yes, simple. And why is the modulus of a positive number worth it? Here it is even simpler: the modulus of a positive number is equal to the number itself: $ \ left | 5\right | = $5; $\left| 129.5\right | = $129.5 etc.

Exit tsіkava rіch: different numbers can be the same module. For example: $ \ left | -5 \right|=\left| 5\right | = $5; $\left| -129.5 \right|=\left| 129.5\right | = $129.5. It doesn't matter if the numbers are the same for some modules: the numbers are the same. Also, it is important to note that the modulus of opposite numbers is equal:

\[\left| -a \right|=\left| a\right|\]

Another important fact: the module is by no means negative. They took the number mi - even if it is positive, if it is negative - the yogo module will always be positive (or in the extreme it will be zero). For this reason, the modulus is often called the absolute value of a number.

In addition, since the module assignment for positive and negative numbers is combined, the module assignment for all numbers is taken globally. And itself: the modulus of the number is equal to the number itself, if the number is positive (or zero), or if the number is equal to the opposite number, if the number is negative. You can write down the same formula:

More is the modulus of zero, but vin zavzhdi is equal to zero. Moreover, zero is alone, as there is no opposite.

In this way, let's take a look at the $ y = \ left | x \right|$ and try to paint the її schedule, then we will see this “daw”:

Graph of the module and butt of perfection

From the bottom of the picture you can clearly see that $ \ left | -m \right|=\left| m \right|$, and the graph of the module does not go any lower than the x-axis. And yet, not everything: the straight line $y=a$ is marked with a red line, so with positive $a$ it gives us two roots: $((x)_(1))$ and $((x)_(2)) $, but let's talk about them later. :)

The cream of a purely algebraic design is more geometric. It is possible that there are two points on the number line: $((x)_(1))$ i $((x)_(2))$. І here viraz $\left| ((x)_(1))-((x)_(2)) \right|$ - don't just move between designated points. Abo, as always, a good vіdrіzka, scho zadnuє tsі points:

Module — tse move between points on a number line

Of which designation is also pronounced, that the module is always negative. Let's move on to the right equals.

Basic formula

Well, harazd, they got out of the appointments. Ale didn’t feel any better. How to check the level, what should be done about this module itself?

Calm but calm. Let's start with the simplest speeches. Let's look at something like this:

\[\left| x\right|=3\]

So, add $x$ module 3. What can you add $x$ to? Well, judging by the appointment, we are totally in power $x=3$. Diyno:

\[\left| 3\right|=3\]

What are the other numbers? Cap nibi pulls, scho є. For example, $ x = -3 $ - for the new $ \ left | -3 \right | = $3, then. necessary equanimity wins.

Then, perhaps, as a joke, think, do we know the numbers? And the axis is broken: there are no more numbers. Rivnyannia $ \ left | x \right|=3$ can only have two roots: $x=3$ and $x=-3$.

Now trochs can be put in order. Let the function $f\left(x \right)$ change under the modulo sign, and the right-handed substitute for the triplet can be set to a sufficient number $a$. We take equal:

\[\left| f\left(x \right) \right|=a\]

Well, and how do you virishuvate? Guessing: $f\left(x \right)$ is quite a function, $a$ is a number. Tobto. vzagali be-yak! For example:

\[\left| 2x+1 \right|=5\]

\[\left| 10x-5 \right|=-65\]

Best respect for each other is equal. One can say about the new eye: there is no root in the new one. Why? Everything is correct: what is needed in the new, so that the module is added to a negative number, which we never know, we already know that the module is a positive number, or zero in the extreme.

And the axis from the first equals is more fun. There are two options here: or under the sign of the module to be positive, and then $ \ left | 2x+1 \right|=2x+1$, otherwise ce viraz is still negative, and so $\left| 2x+1 \right|=-\left(2x+1 \right)=-2x-1$. At the first glance, our equal will be rewritten like this:

\[\left| 2x+1 \right|=5\Rightarrow 2x+1=5\]

And it's easy to come out that the submodular virase $2x+1$ is effectively positive - to the number 5. That's it. we can calmly virishuvati tse rivnyannia - taking away the roots will be shmatkom vіdpovіdі:

Particularly distrustful, they can try to put the knowledge of the root of the vyhіdne equal and reconciliation, which will be a positive number for the module.

Now let's take a look at the negative submodular virusase:

\[\left\( \begin(align)& \left| 2x+1 \right|=5 \\& 2x+1 \lt 0 \\\end(align) \right.\Rightarrow -2x-1=5 \Rightarrow 2x+1=-5\]

Oops! I know everything clearly: we allowed that $2x+1 \lt 0$, and as a result took away that $2x+1=-5$ — ce viraz less than zero. Virishuemo otrimane equal, with whom you already know for sure that knowledge is the root of us:

At the same time, we took away the two returns again: $ x = 2 $ і $ x = 3 $. So, the total cost was three times greater, lower than the simple equal $\left| x \right|=3$, but nothing has changed. Then, perhaps, is there a universal algorithm?

So, such an algorithm is known. І at once mi yogo razberemo.

Zvіlnennya according to the sign of the module

Let's give us equal $ \ left | f\left(x \right) \right|=a$, and $a\ge 0$ (now, as we already know, there is no root). Then you can omit the modulus sign behind this rule:

\[\left| f\left(x \right) \right|=a\Rightarrow f\left(x \right)=\pm a\]

In this rank, our alignment with the module splits into two, but even without a module. Axis and all the expansion! Let's try virishiti kіlka rivnyan. Let's get the axis out of this

\[\left| 5x+4 \right|=10\Rightarrow 5x+4=\pm 10\]

Okremo razglyanaem, if the right is a dozen with a plus, and okremo if with a minus. Maemo:

\[\begin(align)& 5x+4=10\Rightarrow 5x=6\Rightarrow x=\frac(6)(5)=1,2; \\& 5x+4=-10\Rightarrow 5x=-14\Rightarrow x=-\frac(14)(5)=-2.8. \\end(align)\]

From i all! They won two roots: $ x = $1.2 and $ x = -2.8 $. All solutions took literally two rows.

Ok, no food, let's take a look a little more seriously:

\[\left| 7-5x \right|=13\]

I am re-opening the module with plus and minus:

\[\begin(align)& 7-5x=13\Rightarrow -5x=6\Rightarrow x=-\frac(6)(5)=-1,2; \\& 7-5x=-13\Rightarrow -5x=-20\Rightarrow x=4. \\end(align)\]

I'm starting a couple of rows - and the turnaround is ready! As I said, there is nothing collapsible in the modules. It's better to remember the sprat rules. To that we gave and proceeded to the right folding tasks.

Vipadok zminnoy right part

And now let's take a look at this equalization:

\[\left| 3x-2 \right|=2x\]

Tse equal in principle vіdrіznyaєtsya vіd pperednіh. Chim? And we, who are right-handed in the sign of equivalence of the cost of $2x$ - we cannot know for a long time which is more positive and which is negative.

How do you like this time? First, you need to understand once and for all what if the rights of a part of the equal to appear negative, then the equal is not a root- we already know that the modulus cannot equal a negative number.

And in a different way, if the right part is still positive (otherwise it is equal to zero), then you can work the same way as before: just expand the module with a plus sign and a minus sign.

In this way, we formulate a rule for additional functions $f\left(x \right)$ and $g\left(x \right)$ :

\[\left| f\left(x \right) \right|=g\left(x \right)\Rightarrow \left\( \begin(align)& f\left(x \right)=\pm g\left(x \right ) ), \\& g\left(x \right)\ge 0. \\\end(align) \right.\]

We take away our jealousy:

\[\left| 3x-2 \right|=2x\Rightarrow \left\( \begin(align)& 3x-2=\pm 2x, \\& 2x\ge 0. \\\end(align) \right.\]

Well, maybe $2x\ge 0$ we seem to be resting. To be honest, you can stupidly imagine the root, as we take away from the first equal, and reverse: what is the difference between chi and ni.

To that we will untie the very jealousy:

\[\begin(align)& 3x-2=2\Rightarrow 3x=4\Rightarrow x=\frac(4)(3); \\& 3x-2=-2\Rightarrow 3x=0\Rightarrow x=0. \\end(align)\]

Well, yak z tsikh dvoh korenіv satisfying maybe $2x\ge 0$? So both! That's why you have two numbers: $ x = (4) / (3) \; $ i $ x = 0 $. Axis and all solutions.

I suspect that some of the students have already begun to feel bad? Well, let’s look at more folding:

\[\left| ((x)^(3))-3((x)^(2))+x \right|=x-((x)^(3))\]

Even if it looks malicious, in fact, all of them are equal to the “module of good functions” type:

\[\left| f\left(x \right) \right|=g\left(x \right)\]

And it turns out just like that:

\[\left| ((x)^(3))-3((x)^(2))+x \right|=x-((x)^(3))\Rightarrow \left\( \begin(align)& ( (x)^(3))-3((x)^(2))+x=\pm \left(x-((x)^(3)) \right), \\& x-((x )^(3))\ge 0. \\\end(align) \right.\]

From the nervousness of me, then we’ll figure it out - it’s like it’s supposed to be evil (it’s really simple, but we won’t be violating yoga). For the time being, let's take care of otrimanimy equals. We can see the first drop - if the module is opened with a plus sign:

\[((x)^(3))-3((x)^(2))+x=x-((x)^(3))\]

Well, here I realized that it is necessary for all the brothers to be evil, to bring similar ones and marvel at what we see. And see the axis:

\[\begin(align)& ((x)^(3))-3((x)^(2))+x=x-((x)^(3)); \\& 2((x)^(3))-3((x)^(2))=0; \\end(align)\]

Blame the high multiplier $((x)^(2))$ for the shackle and take even simpler equal:

\[((x)^(2))\left(2x-3 \right)=0\Rightarrow \left[ \begin(align)& ((x)^(2))=0 \\& 2x-3 =0 \\\end(align) \right.\]

\[((x)_(1))=0;\quad ((x)_(2))=\frac(3)(2)=1.5.\]

Here we were honored by the important power of creation, for the sake of which we laid out the rich term into multiples: twir is equal to zero, if you want one of the multipliers to be equal to zero.

Now we’ll figure it out for ourselves with other equals, what to enter when opening the module with a “minus” sign:

\[\begin(align)& ((x)^(3))-3((x)^(2))+x=-\left(x-((x)^(3)) \right); \\& ((x)^(3))-3((x)^(2))+x=-x+((x)^(3)); \\& -3((x)^(2))+2x=0; \\& x\left(-3x+2 \right)=0. \\end(align)\]

I know the same: tvir is equal to zero, if it is equal to zero, I want one of the multiples. Maemo:

\[\left[ \begin(align)& x=0 \\& -3x+2=0 \\\end(align) \right.\]

Well, three roots were taken away from mi: $ x = 0 $, $ x = 1.5 $ i $ x = (2) / (3) \; Well, and what about the set of pide at vіdpovіd? For whom, let’s guess what we can doatkove obezhennya at the sight of unevenness:

How to vrahuvati tsiu vimogu? It is so easy to imagine that the root is found and it is reverifiable: there is a difference in the case of tsikh $x$ chi ni. Maemo:

\[\begin(align)& x=0\Rightarrow x-((x)^(3))=0-0=0\ge 0; \\& x=1,5\Rightarrow x-((x)^(3))=1,5-((1,5)^(3)) \lt 0; \\& x=\frac(2)(3)\Rightarrow x-((x)^(3))=\frac(2)(3)-\frac(8)(27)=\frac(10) (27)ge 0; \\end(align)\]

In this rank, the root $ x = $ 1.5 does not belong to us. I have only two roots:

\[((x)_(1))=0;\quad ((x)_(2))=\frac(2)(3).\]

Like a bachite, I didn’t have anything coherent in my mind - the equalization of the modules is always dependent on the algorithm. It is necessary to be better educated on the rich members and inconsistencies. So let's move on to folding tasks - there will already be not one, but two modules.

Alignment with two modules

Dosі mi vyvchali less than the simplest rіvnyannya - there's only one module and more. We corrected the "just now" into the other part of the unevenness, filed a module, so that the result was all equal to $ \ left | f\left(x \right) \right|=g\left(x \right)$ or go beyond the simple $\left| f\left(x \right) \right|=a$.

Ale, the childish garden is over - the hour has come to look more seriously. Let's look at this type:

\[\left| f\left(x \right) \right|=\left| g\left(x \right) \right|\]

The value of the mind "the module is the same as the module". A fundamentally important moment is the presence of other additions and multiples: only one left-handed module, another right-handed module - and nothing more.

Just think at once, that such equal variability is worse, lower those that we have learned and dosі. And the axis i nі: tsі rivnyannya virіshuyusya navіt simpler. Axis formula:

\[\left| f\left(x \right) \right|=\left| g\left(x \right) \right|\Rightarrow f\left(x \right)=\pm g\left(x \right)\]

Mustache! We simply compare submodular virazi, putting a plus or minus sign in front of one of them. And then we will take away two equals - and the root is ready! Everyday dodatkovyh obmezhen, zhestnyh nerіvnosti just. Everything is simple.

Let's try this task:

\[\left| 2x+3 \right|=\left| 2x-7 \right|\]

Elementary, Watson! Opening modules:

\[\left| 2x+3 \right|=\left| 2x-7 \right|\Rightarrow 2x+3=\pm \left(2x-7 \right)\]

Let's take a look at the skin vapadok:

\[\begin(align)& 2x+3=2x-7\Rightarrow 3=-7\Rightarrow \emptyset ; \\& 2x+3=-\left(2x-7 \right)\Rightarrow 2x+3=-2x+7. \\end(align)\]

The first equal has no root. Why if $3=-7$? For what values ​​of $x$? “What the fuck is $x$? Are you stoned? There’s not much $x$ in there,” you say. I will be right. We have obtained equivalence so that we cannot lay aside in the form of exchangeable $x$, and with this equivalence itself is wrong. That is why there is no root.

With other equals, all the trochs are cіkavіshe, but also more and more simply:

Like Bachimo, everything went literally in a couple of rows - we didn’t count the other line of line.

The result has a residual value: $ x = $1.

Well yak? Important? Obviously, no. Let's try again:

\[\left| x-1 \right|=\left| ((x)^(2))-3x+2 \right|\]

I know we are equal to the mind of $ \ left | f\left(x \right) \right|=\left| g\left(x \right) \right|$. To this, we immediately rewrite yoga, revealing the sign of the module:

\[((x)^(2))-3x+2=\pm \left(x-1 \right)\]

It’s possible, someone asks at once: “Hey, what kind of lighthouse is this? Why is “plus-minus” on the right hand side, and not on the left side? Let me explain everything in a moment. In a good way, we are guilty of rewriting our equals like this:

Then we will need to open the arches, transfer all the additions into one line with the sign of parity (shards of parity, obviously, in both directions will be square), that and far away the root. But wait a minute: if “plus or minus” is standing in front of three dodanks (especially if one of them is a square viraz), you seem to look more folding, the situation is lower, if “plus or minus” is less likely to stand in front of two dodanks.

And yet, nothing matters to us to rewrite the day like this:

\[\left| x-1 \right|=\left| ((x)^(2))-3x+2 \right|\Rightarrow \left| ((x)^(2))-3x+2 \right|=\left| x-1 \right|\]

What happened? That is nothing special: they just remembered the lion and the right part of the missions. Dribnitsa, like a troch to forgive us life. :)

In the blink of an eye, it’s tse equal, looking at the options with plus and minus:

\[\begin(align)& ((x)^(2))-3x+2=x-1\Rightarrow ((x)^(2))-4x+3=0; \\& ((x)^(2))-3x+2=-\left(x-1 \right)\Rightarrow ((x)^(2))-2x+1=0. \\end(align)\]

The first equal root is $x=3$ and $x=1$. Another vzagalі є exact square:

\[((x)^(2))-2x+1=((\left(x-1 \right))^(2))\]

There is only one root for this: $x=1$. Ale tse roots were already cut off earlier. In this order, the pіdsumkov vіdpovіd will have only two numbers:

\[((x)_(1))=3;\quad ((x)_(2))=1.\]

Miss vikonan! You can take a pie from the police and get it. There are 2, your average.

Respectful respect. The presence of the same root with different variants of the module expansion means that the outer rich segments are divided into multiples, and the middle of these multiples will be bright. Diyno:

\[\begin(align)& \left| x-1 \right|=\left| ((x)^(2))-3x+2 \right|; \\&\left| x-1 \right|=\left| \left(x-1 \right)\left(x-2 \right) \right|. \\end(align)\]

One of the module's powers: $ \left | acdot b \right|=\left| a \right|\cdot \left| b \right|$ (so that the module is more like the creation of modules), otherwise it can be rewritten like this:

\[\left| x-1 \right|=\left| x-1 \right|\cdot \left| x-2 \right|\]

Yak bachimo, we have the right vinic double multiplier. Now, in order to pick up all the modules from one side, you can blame the whole multiplier for the bow:

\[\begin(align)& \left| x-1 \right|=\left| x-1 \right|\cdot \left| x-2 \right|; \\&\left| x-1 \right|-\left| x-1 \right|\cdot \left| x-2 \right|=0; \\&\left| x-1 \right|\cdot \left(1-\left| x-2 \right| \right)=0. \\end(align)\]

Well, now let's figure out what the addition is to zero, if we want one of the multipliers to reach zero:

\[\left[ \begin(align)& \left| x-1 \right|=0, \\& \left| x-2 \right|=1. \\\end(align) \right.\]

In this rank, two modules were equal to two of the simplest equals, they talked about them at the beginning of the lesson. Such equalities are literally in a couple of rows.

Dane is respected, it is possible, to be superciliously foldable and unstoppable in practice. However, in truth, you can be informed where folded tasks are, lower those, as we can reasonably understand. Those modules can be combined with polynomials, arithmetic roots, and logarithms too. And in such situations, it is possible to reduce the burning riven by the path of guilt of something for the shackle, it can appear more and more than the river.

Now I would like to draw one more equal, as if at first glance I could look hazy. On the new "sticky" rich learners, navit te, yak vvazhayut, sho well sorted out in the modules.

Prote tse rіvnyannya vіrishuєtsya navіt simpler, lower those that we looked at earlier. As soon as you understand something, then you take one more trick to achieve a perfect match with the modules.

Otzhe, Rivnyanya:

\[\left| x-((x)^(3)) \right|+\left| ((x)^(2))+x-2 \right|=0\]

Hі, tse not drukarska pardon: mizh modules itself is a plus. And we need to know, for such $x$ the sum of two modules is equal to zero. :)

Who has a problem? And the problem is that the skin module is a positive number, but in the extreme it is zero. How about adding two positive numbers together? Obviously, I am revisiting a positive number:

\[\begin(align)& 5+7=12 \gt 0; \& 0.004+0.0001=0.0041 \gt 0; \\& 5+0=5 \gt 0. \\\end(align)\]

The rest of the row can be thought of: a single drop, if the sum of the modules is equal to zero, then the skin module is equal to zero:

\[\left| x-((x)^(3)) \right|+\left| ((x)^(2))+x-2 \right|=0\Rightarrow \left\( \begin(align)& \left| x-((x)^(3)) \right|=0, \\& \left|((x)^(2))+x-2 \right|=0.\\\end(align) \right.\]

And if the module is equal to zero? Only in one direction - if pіdmodulny vіraz dоrіvnyuє zero:

\[((x)^(2))+x-2=0\Rightarrow \left(x+2 \right)\left(x-1 \right)=0\Rightarrow \left[ \begin(align)& x=-2 \\& x=1 \\\end(align) \right.\]

In this order, we have three points, in which the first module is reset to zero: 0, 1 and −1; and also two points, in which another module is set to zero: −2 and 1. However, it is necessary for us that both modules are set to zero at the same time, so among the known numbers it is necessary to choose t, which includes up to both sets. Obviously, there is more than one such number: $x=1$ — it will be a residual value.

splitting method

Well, we already looked at the couple of the day before and made up the impersonal receptions. Why do you think everything? And the axis i ni! At once we can look at the final reception - and at the same time the most important. Be aware of the splitting of the rivnyan іz module. What are you talking about? Let's turn back a little and look like a simple equal. For example, tse:

\[\left| 3x-5\right|=5-3x\]

In principle, we already know how to act in such a way, because the standard construction of the form $\left| f\left(x \right) \right|=g\left(x \right)$. Ale try to marvel at the quality of the troch under another hood. More precisely, let's look at the viraz, what to stand under the sign of the module. I’ll guess that the modulus of any number can be equal to the number itself, or it can be the opposite of this number:

\[\left| a \right|=\left\( \begin(align)& a,\quad a\ge 0, \\& -a,\quad a \lt 0. \\end(align) \right.\]

Vlasne, this ambiguity has the whole problem: the number of submodules changes (it’s worth it to change), it’s not clear to us whether it’s positive or negative.

But what if, on the other hand, vimagati, so that the number was positive? For example, let's say $3x-5 \gt 0$ - for which way we are guaranteed to take a positive number under the sign of the module, and which module itself can be called again:

In this rank, our zeal to pretend to be on a linear line, as it is easy to swear:

It's true, all you think about it is more than enough to think $3x-5\gt 0$ - we ourselves managed to help you, so that the module can be unambiguously unlocked. So let's put the knowledge of $x=\frac(5)(3)$ into the mind and reverb it:

To go out, our help does not win over the assigned value of $x$, because Viraz appeared to be equal to zero, but we need it to be strictly greater than zero. Zhurbinka. :(

Ale no big deal! Another option is $3x-5 \lt 0$. More than that: another point $3x-5=0$ — it is necessary to look at it this way, otherwise the decision will be incomprehensible. Let's take a look at the $3x-5 \lt 0$ vipadok:

Obviously, the module is marked with a minus sign. But then again, the situation is wondrous: I’m left-handed, and right-handed at the same viraz:

Tsikavo, with such $x$, $5-3x$ will be more expensive than $5-3x$? In the presence of such equals, the Captain is obvious, choking on his heel, but we know: the ceremony is equal to that, tobto. vono vіrne for whatever the meaning of the change!

And tse means that we are ruled by $x$. Vodnocha we have є obmezhennya:

In other words, it will not be a short number, but a whole interval:

Nareshti lost one more perspective: $3x-5=0$. Everything is simple here: the modulus will be zero, and the modulus of zero will be equal to zero (it’s not directly pronounced):

Ale todі vhіdne rіvnyannya $ \ left | 3x-5 \right|=5-3x$ rewrite like this:

This root was already taken higher, if we looked at the $3x-5\gt 0$ drop. More than that, the price of the root and the solutions equal $3x-5=0$ - the value of the exchange, as we ourselves entered, to reset the module.

In this order, the crim interval is the dominant number for us, which lies on the very end of the interval:


Combining the roots of the equals with the module

Residual proof: $x\in \left(-\infty ;\frac(5)(3) \right]$ It's not too loud to make such crap in the widget until it's simple (essentially - linear) alignment with the module Well, please : this is why the folding of the module is due to the fact that in such equalities it can appear absolutely unreproducible.

Where else is more important: we have carefully developed a universal algorithm for solving the problem with the module! І the whole algorithm is formed from the next steps:

  1. Equate the skin module, which is equal, to zero. We take away sprats of equal;
  2. Put all the numbers equal and put the root on the number line. As a result, a direct rise to a sprinkling of intervals, on the skin of any of the modules, unambiguously rises;
  3. Virishiti vihіdne іvnyannja for dermal interval and ob'єdnati otrimaniі vіdpovіdі.

From i all! Less than one food is left: where do you go your own roots, cut off on the 1st crochet? Suppose we have two roots: $ x = 1 $ i $ x = 5 $. The stench rose numerically straight for 3 pieces:

Splitting the numerical axis on the interval for an additional point

Well, what are the intervals here? I realized that there are three of them:

  1. Naylivishy: $x \lt 1$ — the single element itself is not included in the interval;
  2. Central: $1\le x \lt 5$ - the axis here is one per interval to enter, prote not to enter five;
  3. The right one: $x\ge 5$ - Five days to get in here!

I guess you already understood the law. The leather interval includes the left end and does not include the right.

At first glance, such a record may appear unhandled, illogical, and seem to be hazy. Ale turn: after a little training, you will discover that such a pidkhid itself is the most superior and, for that matter, does not unequivocally develop modules. It’s better to win such a scheme, then think twice: take a left / right turn at the current interval, or throw yoga on the offensive.

On which lesson will end. Take charge of the task for self-sufficiency, train, compete with influences - and we will work in the coming lesson, which will be assigned to the nervousness of the modules.

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