Properties of Periodic Function

Q. The period of the function $f\left(x\right)=3\sin 2\sqrt{3}x+2\cos 5\sqrt{3}x$ is

1. $\frac{2\pi }{\sqrt{3}}$
2. $\frac{\pi }{3}$
3. $\frac{\pi }{\sqrt{3}}$
4. $2\pi$

Q. Fundamental period of the function $f\left(x\right)=\sin \sqrt{x}$ is

1. $\sqrt{\pi }$
2. $2\pi$
3. $\pi$
4. None of these

Q.

What is the period of f(x) = Sinx. Cos3x ?

1. $2\pi$

2. $1$

3. $2$

4. $\frac{\pi }{2}$