Differentiation Question 257
Question: The differential coefficient of $ f[\log (x)] $ when $ f(x)=\log x $ is
[Kurukshetra CEE 1998; DCE 2000]
Options:
A) $ x\log x $
B) $ \frac{x}{\log x} $
C) $ \frac{1}{x\log x} $
D) $ \frac{\log x}{x} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ \because f(x)=\log x $ ;
$ \therefore f[\log x]=\log \log x $
$ f’[\log x]=\frac{1}{\log x}.\frac{d}{dx}\log x=\frac{1}{x\log x} $ .
BETA
