A) 0
B) 1
C) 2
D) Infinite
Correct Answer: B
Solution :
\[f(x)=\cos x+\cos (\sqrt{2}x)\] \[f'(x)=-\sin x-\sqrt{2}\sin (\sqrt{2}x)=0\] Hence \[x=0\]is the only solution. \[f''(x)=-\cos x-2\cos (\sqrt{2}x)<0\]at \[x=0\] Hence maxima occurs at \[x=0\].You need to login to perform this action.
You will be redirected in
3 sec