If $x=\cos\theta+i\sin\theta$ the value of $x^{n}+\large\frac{1}{x^{n}}$ is

Question

$$\begin{array}{1 1}(1)2\cos n\theta&(2)2\;i\sin n\theta\\(3)2\sin n\theta&(4)2\; i\cos n\theta\end{array}$$