Functions Question 64

Question: $ \underset{x\to 0}{\mathop{\lim }},[ \frac{1}{x}-\frac{\log (1+x)}{x^{2}} ] $ =

Options:

A) ½

B) ?1/2

C) 1

D) ?1

Show Answer

Answer:

Correct Answer: A

Solution:

Expand $ \log ,(1+x) $ and then solve. Aliter : Apply L-Hospital?s rule, $ \underset{x\to 0}{\mathop{\lim }}[ \frac{x-\log ,(1+x)}{x^{2}} ] $ $ =\underset{x\to 0}{\mathop{\lim }},\frac{1-\frac{1}{1+x}}{2x} $ $ =\underset{x\to 0}{\mathop{\lim }},\frac{1}{2},{{( \frac{1}{1+x} )}^{2}}=\frac{1}{2}. $