Math Problem Statement

lim_(x→0) ( sin (x))^(100)/(x^(99) sin (2x))

Solution

To evaluate the limit

limx0sin100(x)x99sin(2x),\lim_{x \to 0} \frac{\sin^{100}(x)}{x^{99} \sin(2x)},

let's break it down step by step.


Step 1: Simplify the powers of sin(x)\sin(x)

Using the small-angle approximation, sin(x)x\sin(x) \approx x as x0x \to 0. Therefore: sin100(x)x100.\sin^{100}(x) \approx x^{100}.


Step 2: Simplify sin(2x)\sin(2x)

Using the small-angle approximation again, sin(2x)2x\sin(2x) \approx 2x as x0x \to 0.

Thus: sin(2x)2x.\sin(2x) \approx 2x.


Step 3: Substitute approximations into the limit

Substituting these into the limit, we get: limx0sin100(x)x99sin(2x)limx0x100x992x.\lim_{x \to 0} \frac{\sin^{100}(x)}{x^{99} \sin(2x)} \approx \lim_{x \to 0} \frac{x^{100}}{x^{99} \cdot 2x}.

Simplify the numerator and denominator: x100x992x=x1002x100=12.\frac{x^{100}}{x^{99} \cdot 2x} = \frac{x^{100}}{2x^{100}} = \frac{1}{2}.


Step 4: Final result

The limit evaluates to: 12\boxed{\frac{1}{2}}

Let me know if you have questions or need clarification! 😊


Related Questions:

  1. How do small-angle approximations help simplify trigonometric limits?
  2. What is the derivation of sin(x)x\sin(x) \approx x for small xx?
  3. How can we use L'Hôpital's Rule to solve this limit?
  4. What are common strategies to evaluate limits involving trigonometric functions?
  5. How does the approximation sin(2x)2x\sin(2x) \approx 2x compare to Taylor series expansion?

Tip: For limits involving trigonometric functions near 0, remember small-angle approximations!

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Math Problem Analysis

Mathematical Concepts

Limits
Small-angle approximation
Trigonometric functions
Simplification of expressions

Formulas

sin(x) ≈ x for small x
sin(2x) ≈ 2x for small x
Limit of a function as x → 0

Theorems

Small-angle approximation for sin(x)
Limit laws

Suitable Grade Level

Grades 11-12