Applications Of Derivatives Question 406
Question: If $ f(x)=\sin x-\frac{x}{2} $ is increasing function, then
[MP PET 1987]
Options:
A) $ 0<x<\frac{\pi }{3} $
B) $ -\frac{\pi }{3}<x<0 $
C) $ -\frac{\pi }{3}<x<\frac{\pi }{3} $
D) $ x=\frac{\pi }{2} $
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Answer:
Correct Answer: C
Solution:
$ f(x)=\sin x-\frac{x}{2}\Rightarrow f’(x)=\cos x-\frac{1}{2} $
$ f’(x)>0 $ for increasing function
Obviously it is increasing for $ -\frac{\pi }{3}<x<\frac{\pi }{3} $ .
BETA
