A) \[\left( \frac{\pi }{4},\frac{\pi }{2} \right)\]
B) \[\left( -\frac{\pi }{2},\frac{\pi }{4} \right)\]
C) \[\left( 0,\frac{\pi }{2} \right)\]
D) \[\left( -\frac{\pi }{2},\frac{\pi }{2} \right)\]
Correct Answer: B
Solution :
[b] \[f'(x)=\frac{1}{1+{{(\sin x+\cos x)}^{2}}}(\cos x-\sin x)\] \[f(x)\]is increasing if \[\cos x-\sin x>0\] Or \[\cos x>\sin x\] Hence, \[f(x)\]is increasing when \[x\in \left( -\frac{\pi }{2},\frac{\pi }{4} \right)\]
You need to login to perform this action.
You will be redirected in
3 sec
