Math Problem Statement

Evaluate the limit: lim(x→0) (e^x - 1) / tan(x)

Solution

To evaluate the limit:

limx0ex1tanx\lim_{x \to 0} \frac{e^x - 1}{\tan x}

we can proceed by analyzing the behavior of the function as x0x \to 0.

Step-by-Step Solution

  1. Identify the Form: As x0x \to 0, both ex1e^x - 1 and tanx\tan x approach 0, giving us an indeterminate form 00\frac{0}{0}. Therefore, we can apply L'Hôpital's Rule, which states that for limits of the form 00\frac{0}{0}, we can take the derivatives of the numerator and denominator.

  2. Differentiate the Numerator and Denominator:

    • The derivative of the numerator ex1e^x - 1 is exe^x.
    • The derivative of the denominator tanx\tan x is sec2x\sec^2 x.

    So the limit becomes: limx0exsec2x=limx0excos2x\lim_{x \to 0} \frac{e^x}{\sec^2 x} = \lim_{x \to 0} e^x \cos^2 x

  3. Evaluate the Limit: Now, substitute x=0x = 0 into excos2xe^x \cos^2 x.

    • e0=1e^0 = 1
    • cos20=1\cos^2 0 = 1

    Thus: limx0excos2x=11=1\lim_{x \to 0} e^x \cos^2 x = 1 \cdot 1 = 1

Final Answer

limx0ex1tanx=1\lim_{x \to 0} \frac{e^x - 1}{\tan x} = 1

Would you like further details or have any questions?


Here are some related questions that might interest you:

  1. How would the limit change if we had limx0ln(1+x)tanx\lim_{x \to 0} \frac{\ln(1+x)}{\tan x}?
  2. What if we replaced ex1e^x - 1 with sinx\sin x in this limit?
  3. Can we use Taylor expansions to approximate limits like this one?
  4. How does the behavior of ex1e^x - 1 compare to tanx\tan x as x0x \to 0?
  5. What is L'Hôpital's Rule, and when should it be applied?

Tip: In problems involving indeterminate forms, L'Hôpital's Rule is a powerful tool, but always remember to check if simpler methods (like factoring or simplification) can solve the problem more efficiently.

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Math Problem Analysis

Mathematical Concepts

Limits
Calculus
Indeterminate Forms

Formulas

L'Hôpital's Rule
Limit of (e^x - 1) / x as x approaches 0
Limit of tan(x) / x as x approaches 0

Theorems

L'Hôpital's Rule

Suitable Grade Level

Grades 11-12