Functions Question 214

Question: $ \underset{x\to 0}{\mathop{\lim }},\sin ( \frac{1}{x} ) $ is

[SCRA 1996]

Options:

A) 0

B) 1

C) ?1

D) Does not exist

Show Answer

Answer:

Correct Answer: D

Solution:

$ \underset{x\to {0^{-}}}{\mathop{\lim }},f(x)=\underset{h\to 0}{\mathop{\lim }},f(0-h) $ $ =\underset{h\to 0}{\mathop{\lim }}\sin ,( \frac{-1}{h} )=\underset{h\to 0}{\mathop{\lim }},-\sin \frac{1}{h} $ = ? 1 (finite number lies between ? 1 to 1) $ \underset{x\to {0^{+}}}{\mathop{\lim }},f(x)=\underset{h\to 0}{\mathop{\lim }},f(0+h) $ $ =\underset{h\to 0}{\mathop{\lim }},\sin ( \frac{1}{h} ) $ = (finite number lies between 0 to 1) $ \because \underset{x\to {0^{-}}}{\mathop{\lim }},f(x)\ne \underset{x\to {0^{+}}}{\mathop{\lim }},f(x) $ ; \ $ \underset{x\to 0}{\mathop{\lim }},\sin ( \frac{1}{x} ) $ does not exist.