Math Problem Statement

lim x->0 sin 2x/sin 6x

Solution

To solve the limit limx0sin2xsin6x\lim_{x \to 0} \frac{\sin 2x}{\sin 6x}, we'll use the small angle approximation:

sinxxasx0\sin x \approx x \quad \text{as} \quad x \to 0

Step-by-Step Solution:

  1. Apply the small angle approximation: sin2x2xandsin6x6xasx0\sin 2x \approx 2x \quad \text{and} \quad \sin 6x \approx 6x \quad \text{as} \quad x \to 0

  2. Substitute these approximations into the limit: limx0sin2xsin6xlimx02x6x\lim_{x \to 0} \frac{\sin 2x}{\sin 6x} \approx \lim_{x \to 0} \frac{2x}{6x}

  3. Simplify the expression: limx02x6x=limx026=13\lim_{x \to 0} \frac{2x}{6x} = \lim_{x \to 0} \frac{2}{6} = \frac{1}{3}

Final Answer:

limx0sin2xsin6x=13\lim_{x \to 0} \frac{\sin 2x}{\sin 6x} = \frac{1}{3}

Would you like more details or have any questions about this solution?

Here are 5 related questions to deepen your understanding:

  1. How does the small angle approximation work for other trigonometric functions like cosx\cos x and tanx\tan x?
  2. Can you solve limx0sin(3x)sin(9x)\lim_{x \to 0} \frac{\sin(3x)}{\sin(9x)} using a similar approach?
  3. How does L'Hôpital's rule apply to this limit problem?
  4. What would be the result of limx0sin2(2x)sin2(6x)\lim_{x \to 0} \frac{\sin^2(2x)}{\sin^2(6x)}?
  5. What is the general approach for evaluating limits involving trigonometric functions as xx approaches 0?

Tip: When evaluating limits, particularly trigonometric ones, the small angle approximation is a powerful tool to simplify the problem.

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Math Problem Analysis

Mathematical Concepts

Limits
Trigonometry
Small angle approximation

Formulas

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Theorems

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Suitable Grade Level

College Level