Limits Continuity And Differentiability Question 97

Question: The value of f(0) so that the function $ f(x)=\frac{2x-{{\sin }^{-1}}x}{2x+{{\tan }^{-1}}x} $ is continuous at each point in its domain, is equal to

Options:

A) 2

B) 1/3

C) 2/3

D) -1/3

Show Answer

Answer:

Correct Answer: B

Solution:

The function f is clearly continuous at each point in its domain except possibly at x=0.

Given that f(x) is continuous at x=0.

$ \therefore f(0)=\underset{x\to 0}{\mathop{\lim }}f(x) $

$ =\underset{x\to 0}{\mathop{\lim }}\frac{2x-{{\sin }^{-1}}x}{2x+{{\tan }^{-1}}x} $

$ =\underset{x\to 0}{\mathop{\lim }}\frac{2-(si{n^{-1}}x)/x}{2+({{\tan }^{-1}}x)x}=\frac{1}{3} $