Math Problem Statement

Select all correct statements regarding calculus and algebra in the given intervals and functions.

Solution

Let us analyze the mathematical statements from the image step by step.


First Statement

"На интервале (π/2,3π/2)(\pi/2, 3\pi/2) найдется точка cc, в которой производная функции y=cosxy = \cos x равна нулю."

  • The derivative of y=cosxy = \cos x is y=sinxy' = -\sin x.
  • We are asked to check if sinx=0-\sin x = 0 within the interval (π/2,3π/2)(\pi/2, 3\pi/2).

Within this interval:

  • The sine function, sinx\sin x, equals zero at x=πx = \pi, which lies in (π/2,3π/2)(\pi/2, 3\pi/2).

Conclusion: This statement is true.


Second Statement

"Точка x0=0x_0 = 0 — точка строгого локального минимума функции y=xy = |x|."

  • The function y=xy = |x| is defined as: x, & x \geq 0 \\ -x, & x < 0 \end{cases}$$
  • At x0=0x_0 = 0, the value of yy is 00. The value increases as xx moves away from 00 in either direction (y>0y > 0 for x0x \neq 0).

Conclusion: x0=0x_0 = 0 is indeed a strict local minimum point for y=xy = |x|. This statement is true.


Third Statement

"Поскольку функция y=xy = |x| в точке x0=0x_0 = 0 принимает экстремальное значение и имеет конечную производную y(x0)y'(x_0), то y(x0)=0y'(x_0) = 0."

  • For y=xy = |x|, the derivative is: 1, & x > 0 \\ -1, & x < 0 \end{cases}$$
  • At x=0x = 0, the derivative does not exist because the left-hand derivative (1-1) does not equal the right-hand derivative (11).

Conclusion: This statement is false, as the derivative at x0=0x_0 = 0 is not defined.


Fourth Statement

"На интервале (0,2)(0, 2) найдется точка cc, в которой производная функции y=x3y = x^3 равна y(c)=4y'(c) = -4."

  • The derivative of y=x3y = x^3 is y=3x2y' = 3x^2.
  • We are asked to solve 3x2=43x^2 = -4 for some x(0,2)x \in (0, 2).
  • Since 3x203x^2 \geq 0 for all xx, it is impossible for 3x23x^2 to equal 4-4.

Conclusion: This statement is false.


Fifth Statement

"На интервале (0,2)(0, 2) найдется точка cc, в которой для производных функций f(x)=x4f(x) = x^4 и g(x)=xg(x) = x выполняется соотношение f(c)=8g(c)f'(c) = 8g'(c)."

  • The derivatives are: f(x)=4x3,g(x)=1.f'(x) = 4x^3, \quad g'(x) = 1.
  • Substituting into the equation f(c)=8g(c)f'(c) = 8g'(c), we get: 4c3=8    c3=2    c=23.4c^3 = 8 \implies c^3 = 2 \implies c = \sqrt[3]{2}.
  • Since c=231.26c = \sqrt[3]{2} \approx 1.26, which lies in the interval (0,2)(0, 2), such a point cc exists.

Conclusion: This statement is true.


Final Answer

The correct statements are:

  1. The first statement.
  2. The second statement.
  3. The fifth statement.

Would you like a detailed explanation of any specific part? Let me know!


5 Related Questions

  1. What is the process for finding critical points of a function in a given interval?
  2. How do we determine if a point is a local minimum or maximum using derivatives?
  3. Why does the derivative of y=xy = |x| not exist at x=0x = 0?
  4. How do we solve equations involving cubic roots, such as c3=2c^3 = 2?
  5. What are the conditions for applying the mean value theorem for derivatives?

Tip

When analyzing derivatives, always check for both existence and continuity to avoid incorrect conclusions!

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivative Analysis
Critical Points
Absolute Value Function
Cubic Functions

Formulas

y' = -sin(x) (derivative of cos(x))
y' = 3x^2 (derivative of x^3)
f'(x) = 4x^3 (derivative of x^4)
g'(x) = 1 (derivative of x)
y = |x|

Theorems

Critical Points Theorem
Properties of Absolute Value Function
Existence of Derivatives

Suitable Grade Level

Undergraduate Calculus