A) 1
B) \[-1\]
C) 2
D) 0
E) \[-2\]
Correct Answer: C
Solution :
\[f(x)=a\sin x+\frac{1}{3}\sin 3x\] \[f(x)=a\cos x+\frac{3}{3}\cos 3x=0,\]at\[x=\frac{\pi }{3}\] \[\Rightarrow \] \[a\cos \frac{\pi }{3}+\cos \frac{\pi }{3}.3=0\] \[\Rightarrow \] \[a.\frac{1}{2}+(-1)=0\] \[\Rightarrow \] \[a=2\]You need to login to perform this action.
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