trigonometry

Question: The sum $S=\sin \theta +\sin 2\,\theta +....+\sin \,n\theta ,$ equals

1) $\sin \frac{1}{2}(n+1)\text{ }\theta \sin \frac{1}{2}n\text{ }\theta /\sin \frac{\theta }{2}$

2) $\cos \frac{1}{2}(n+1)\text{ }\theta \sin \frac{1}{2}n\theta /\sin \frac{\theta }{2}$

3) $\sin \frac{1}{2}(n+1)\theta \cos \frac{1}{2}n\theta /\sin \frac{\theta }{2}$

4) $\cos \frac{1}{2}(n+1)\theta \cos \frac{1}{2}n\theta /\sin \frac{\theta }{2}$

Solution:

Explanation: No Solution

Rate this question:

★ ★ ★ ★ ★

Average rating: (0 votes)