Math Problem Statement

. Find the limit. lim π‘₯β†’0 tan (π‘₯) /x

Solution

We need to evaluate the limit:

lim⁑xβ†’0tan⁑(x)x\lim_{x \to 0} \frac{\tan(x)}{x}

Step 1: Use the Standard Limit Result

A well-known trigonometric limit states:

lim⁑xβ†’0sin⁑(x)x=1\lim_{x \to 0} \frac{\sin(x)}{x} = 1

We can rewrite tan⁑(x)\tan(x) in terms of sine and cosine:

tan⁑(x)x=sin⁑(x)xβ‹…1cos⁑(x)\frac{\tan(x)}{x} = \frac{\sin(x)}{x} \cdot \frac{1}{\cos(x)}

Taking the limit as x→0x \to 0:

lim⁑xβ†’0tan⁑(x)x=lim⁑xβ†’0sin⁑(x)xβ‹…lim⁑xβ†’01cos⁑(x)\lim_{x \to 0} \frac{\tan(x)}{x} = \lim_{x \to 0} \frac{\sin(x)}{x} \cdot \lim_{x \to 0} \frac{1}{\cos(x)}

From the standard limit result:

lim⁑xβ†’0sin⁑(x)x=1\lim_{x \to 0} \frac{\sin(x)}{x} = 1

And since cos⁑(0)=1\cos(0) = 1, we get:

lim⁑xβ†’01cos⁑(x)=1\lim_{x \to 0} \frac{1}{\cos(x)} = 1

Thus, multiplying both limits:

1Γ—1=11 \times 1 = 1

Final Answer:

lim⁑xβ†’0tan⁑(x)x=1\lim_{x \to 0} \frac{\tan(x)}{x} = 1

Would you like further explanation or more examples?

Related Questions:

  1. What is lim⁑xβ†’0sin⁑(x)x\lim_{x \to 0} \frac{\sin(x)}{x} and how is it derived?
  2. How can L'HΓ΄pital’s Rule be used to evaluate lim⁑xβ†’0tan⁑(x)x\lim_{x \to 0} \frac{\tan(x)}{x}?
  3. What are the small-angle approximations for sine and tangent?
  4. How does the Taylor series expansion of tan⁑(x)\tan(x) help in evaluating limits?
  5. What is the limit of tan⁑(x)βˆ’xx3\frac{\tan(x) - x}{x^3} as xβ†’0x \to 0?

Tip:

For small angles, sin⁑(x)β‰ˆx\sin(x) \approx x and tan⁑(x)β‰ˆx\tan(x) \approx x. These approximations are useful for quick limit evaluations.

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Math Problem Analysis

Mathematical Concepts

Limits
Trigonometry
Sine and Cosine Functions

Formulas

lim(x→0) sin(x)/x = 1
tan(x) = sin(x)/cos(x)

Theorems

Standard Limit Result
Trigonometric Limit Theorem

Suitable Grade Level

Grades 11-12