Math Problem Statement

lim x->0 sin 7x + tan 3x - sin 5x/tan 9x - tan 3x- sin x soal itu limit trigonometri tanpa substitusi

Solution

To solve the limit limx0sin(7x)+tan(3x)sin(5x)tan(9x)tan(3x)sin(x)\lim_{x \to 0} \frac{\sin(7x) + \tan(3x) - \sin(5x)}{\tan(9x) - \tan(3x) - \sin(x)} without substitution, we will use the fact that for small values of xx, sin(x)x\sin(x) \approx x and tan(x)x\tan(x) \approx x. This allows us to approximate each trigonometric function by its linear approximation near 0.

Let's approximate the functions:

sin(7x)7x,sin(5x)5x,sin(x)x\sin(7x) \approx 7x, \quad \sin(5x) \approx 5x, \quad \sin(x) \approx x tan(3x)3x,tan(9x)9x\tan(3x) \approx 3x, \quad \tan(9x) \approx 9x

Substituting these approximations into the limit:

limx07x+3x5x9x3xx\lim_{x \to 0} \frac{7x + 3x - 5x}{9x - 3x - x}

Simplifying the expressions:

limx0(7x+3x5x)(9x3xx)=limx05x5x=limx01=1\lim_{x \to 0} \frac{(7x + 3x - 5x)}{(9x - 3x - x)} = \lim_{x \to 0} \frac{5x}{5x} = \lim_{x \to 0} 1 = 1

Thus, the limit is 1\boxed{1}.

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

  1. What is the limit of limx0sin(2x)sin(x)tan(4x)tan(2x)\lim_{x \to 0} \frac{\sin(2x) - \sin(x)}{\tan(4x) - \tan(2x)}?
  2. How do small angle approximations help in evaluating trigonometric limits?
  3. Can the same technique be used for limits involving cos(x)\cos(x)?
  4. How does the Taylor series expansion of trigonometric functions relate to this limit?
  5. What happens if higher-order approximations are used for sin(x)\sin(x) and tan(x)\tan(x)?

Tip: When working with limits of trigonometric functions as xx approaches 0, small angle approximations (sin(x)x\sin(x) \approx x and tan(x)x\tan(x) \approx x) are often very useful for simplifying the expression.