Question 24If $\theta$ is a constant such that $0\lt\theta\lt\pi$ and $x+\frac1x=2\cos\theta,$ then for each positive integer $n,$ $x^n+\frac1{x^n}$ equals$2\cos\theta$$2^n\cos\theta$$2\cos^n\theta$$2\cos n\theta$$2^n\cos^n\theta$