If $n \in N$ and the period of $\frac{\cos(nx)}{\sin(x/n)}$ is $4\pi$,then $n$ is equal to

Which of the following function$(s)$ is/are periodic?

The period of the function $f(x) = \log(\cos 2x) + \sin 4x$ is :-

Let $f(x) = \sin^2 x + \cos^4 x + 2$ and $g(x) = \cos(\cos x) + \cos(\sin x)$. Also,let the period of $f(x)$ and $g(x)$ be $T_1$ and $T_2$ respectively,then:

The period of $\cos(7x - 5)$ is

The period of $\frac{\sin x}{\cos 3x} + \frac{\sin 3x}{\cos 9x} + \frac{\sin 9x}{\cos 27x} + \frac{\sin 27x}{\cos 81x}$ is