Integral of trigonometric functions

Thread starter darkmagic
Start date Dec 1, 2009
Tags

Functions Integral Trigonometric Trigonometric functions

Dec 1, 2009

darkmagic

Homework Statement

How can I integrate this:

\int sin (nt) sin (n \pi t) dt

This actually in the Fourier series.

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Dec 1, 2009

LCKurtz

Science Advisor

Homework Helper

Use the trig identity:

\sin\theta\sin\phi=\frac{\cos{(\theta-\phi)}-\cos{(\theta+\phi)}}{2}

Dec 1, 2009

Donaldos

You can use the following identity:

\sin a \sin b=\frac{\cos(a-b)-\cos(a+b)} 2

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