Math Problem Statement

Suppose C is a nonzero real number. Evaluate the following limit, if possible. If the limit does not exist, explain why not: lim (x -> 0) [C * tan^2(x) * csc(x)] / x.

Solution

We are tasked with evaluating the following limit:

limx0Ctan2(x)csc(x)x\lim_{x \to 0} \frac{C \cdot \tan^2(x) \cdot \csc(x)}{x}

where CC is a nonzero real number.

Step-by-step evaluation:

  1. Break down the expression: The given expression can be rewritten as: limx0Ctan2(x)csc(x)x=Climx0tan2(x)csc(x)x\lim_{x \to 0} \frac{C \cdot \tan^2(x) \cdot \csc(x)}{x} = C \cdot \lim_{x \to 0} \frac{\tan^2(x) \cdot \csc(x)}{x} Since CC is a constant, we can focus on evaluating the limit of the function tan2(x)csc(x)x\frac{\tan^2(x) \cdot \csc(x)}{x}.

  2. Recall important approximations near zero: As x0x \to 0, we can use the following approximations:

    • tan(x)x\tan(x) \approx x, meaning tan2(x)x2\tan^2(x) \approx x^2.
    • csc(x)=1sin(x)1x\csc(x) = \frac{1}{\sin(x)} \approx \frac{1}{x}.

    Using these, we approximate the expression: tan2(x)csc(x)xx21xx=x2x2=1.\frac{\tan^2(x) \cdot \csc(x)}{x} \approx \frac{x^2 \cdot \frac{1}{x}}{x} = \frac{x^2}{x^2} = 1.

  3. Final answer: Since the limit of tan2(x)csc(x)x\frac{\tan^2(x) \cdot \csc(x)}{x} approaches 1 as x0x \to 0, the overall limit is: C1=C.C \cdot 1 = C.

Thus, the value of the limit is:

C.\boxed{C}.

Would you like more details or have further questions? Here are some related questions for further exploration:

  1. How would this limit change if C=0C = 0?
  2. Why do tan(x)\tan(x) and sin(x)\sin(x) have similar behaviors near zero?
  3. How do small angle approximations help in calculating limits?
  4. Can you calculate the limit without using approximations?
  5. What other limits involving trigonometric functions are useful?

Tip: Small angle approximations are very useful for evaluating limits of trigonometric functions near zero.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Limits
Trigonometric functions
Small angle approximations

Formulas

tan(x) ≈ x for x near 0
csc(x) = 1/sin(x)
lim (x -> 0) [tan^2(x) * csc(x)] / x ≈ 1

Theorems

Limit definition
Small angle approximations

Suitable Grade Level

College/University Calculus