# Math Help - Sum of sines.

1. ## Sum of sines.

Prove: $sin (\frac{\pi }{25}) + sin (\frac{2\pi }{25}) +...+ sin (24\frac{\pi }{25})=cotg\frac{\pi }{25}$

2. Originally Posted by arm
Prove: $sin (\frac{\pi }{25}) + sin (\frac{2\pi }{25}) +...+ sin (24\frac{\pi }{25})=cotg\frac{\pi }{25}$
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