Differentiation Question 206

Question: If $ \underset{x\to a}{\mathop{\lim }}[ \frac{f(x)}{g(x)} ] $ exist, then which one of the following correct-

Options:

A) Both $ \underset{x\to a}{\mathop{\lim }}f(x) $ and $ \underset{x\to a}{\mathop{\lim }}g(x) $ must exist

B) $ \underset{x\to a}{\mathop{\lim }}f(x) $ need not exist but $ \underset{x\to a}{\mathop{\lim }}g(x) $ must exist

C) Both $ \underset{x\to a}{\mathop{\lim }}f(x) $ and $ \underset{x\to a}{\mathop{\lim }}g(x) $ need not exist

D) None of these

Show Answer

Answer:

Correct Answer: D

Solution:

[d] $ f(x)=x,g(x)=\frac{1}{x} $

$ \underset{x\to 0}{\mathop{\lim }}f(x)=0,\underset{x\to 0}{\mathop{\lim }}g(x)= $ does not exist But $ \underset{x\to 0}{\mathop{\lim }}[ \frac{f(x)}{g(x)} ]=\underset{x\to 0}{\mathop{\lim }}[ x^{2} ]=0 $ Hence, none of these is only true option.