Question

The period of the function $f(x)={\cos }^{2}3x+\tan 4x$ is

• A. $\pi /3$
• B. $\pi /4$
• C. $\pi /6$
• D. $\pi$

Answer 1

Answer: (D)

$f(x)=(1/2)(1+\cos 6x)+\tan 4x$.
The period of $\cos 6x$ is $2\pi /6=\pi /3$ and the period of $\tan 4x$ is $\pi /4$.
Hence the period of $f$ is l.c.m. of $\pi /3$ and $\pi /4=\pi$.