Math Problem Statement

  1. Найти точку С,которая удовлетворяет условию теоремы Ролля для функции 3 y x x = − на отрезке y = − 1;0 и y = 0;1
  2. Найти такую точку, лежащую на дуге 2 y x = параболы между точками A(1;1) и B(3;9) , чтобы касательная, проходящая через эту точку, была параллельна хорде АВ

Solution

Let's first address the limit problem presented in the image:

The expression is:

limx0(cos(2x))1x2\lim_{{x \to 0}} \left( \cos(2x) \right)^{\frac{1}{x^2}}

To solve this limit, we need to analyze the behavior of the expression as xx approaches 0.

Step 1: Simplify the Cosine Expression

As xx approaches 0, cos(2x)\cos(2x) approaches cos(0)=1\cos(0) = 1. However, because the exponent is 1x2\frac{1}{x^2}, we need to be more careful.

Step 2: Take the Natural Logarithm

To evaluate the limit, we can take the natural logarithm:

L=limx0ln((cos(2x))1x2)=limx01x2ln(cos(2x))L = \lim_{{x \to 0}} \ln \left( \left(\cos(2x)\right)^{\frac{1}{x^2}} \right) = \lim_{{x \to 0}} \frac{1}{x^2} \ln \left( \cos(2x) \right)

Step 3: Expand ln(cos(2x))\ln(\cos(2x)) using Taylor Series

Near x=0x = 0, cos(2x)\cos(2x) can be approximated by its Taylor series:

cos(2x)12x2\cos(2x) \approx 1 - 2x^2

So,

ln(cos(2x))ln(12x2)\ln(\cos(2x)) \approx \ln\left(1 - 2x^2\right)

Using the approximation ln(1+y)y\ln(1 + y) \approx y when yy is small,

ln(12x2)2x2\ln\left(1 - 2x^2\right) \approx -2x^2

Thus,

L=limx01x2(2x2)=limx02=2L = \lim_{{x \to 0}} \frac{1}{x^2} \cdot (-2x^2) = \lim_{{x \to 0}} -2 = -2

Step 4: Exponentiate to Find the Original Limit

The original limit can now be found by exponentiating:

limx0(cos(2x))1x2=eL=e2\lim_{{x \to 0}} \left(\cos(2x)\right)^{\frac{1}{x^2}} = e^L = e^{-2}

So the limit is:

e2\boxed{e^{-2}}

Summary

The limit limx0(cos(2x))1x2\lim_{{x \to 0}} \left( \cos(2x) \right)^{\frac{1}{x^2}} evaluates to e2e^{-2}.


Would you like details on the other questions presented in the image? If so, please let me know!

Here are 8 related questions for further exploration:

  1. How does the Taylor series expansion of trigonometric functions help in solving limits?
  2. What is the general form of L'Hopital's Rule, and when is it applied?
  3. What are common strategies for evaluating limits that approach indeterminate forms?
  4. How can you determine if a function is continuous at a given point?
  5. What is the significance of the exponential function in calculus, particularly exe^x?
  6. How do you solve limits involving logarithmic and exponential functions?
  7. How does the approximation ln(1+y)y\ln(1 + y) \approx y work, and under what conditions is it valid?
  8. Can the limit above be evaluated using series expansion directly without logarithms?

Tip: When dealing with limits involving exponents, taking the natural logarithm can often simplify the problem by transforming the exponential limit into a product or sum, which is easier to evaluate.

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Taylor Series

Formulas

Limit involving exponential function

Theorems

L'Hopital's Rule

Suitable Grade Level

Advanced College Level