Differentiation Question 130

Question: Let $ f(x)= \begin{matrix} x\sin ( \frac{1}{x} )+\sin ( \frac{1}{x^{2}} ),x\ne 0 \\ 0,x=0 \\ \end{matrix} . $ then $ \underset{x\to \infty }{\mathop{\lim }}f(x) $ equals

Options:

A) 0

B) $ -1/2 $

C) 1

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

[c] $ \underset{x\to \infty }{\mathop{\lim }}f(x)=\underset{x\to \infty }{\mathop{\lim }}x\sin ( \frac{1}{x} )+\sin ( \frac{1}{x^{2}} ) $

$ =\underset{x\to \infty }{\mathop{\lim }}\frac{\sin ( \frac{1}{x} )}{( \frac{1}{x} )}+\underset{x\to \infty }{\mathop{\lim }}\sin ( \frac{1}{x^{2}} )=1+0=1. $