# Help me please, A0 fourier series for this Sawtooth wave

I need to know for this wave sub zero, the correct answer is a0=-2V/Pi, but I do not know how to get to that answer. Help me please the imagen its the series.

This is the sawtooth wave http://s9.postimage.org/42uc7x0pp/IMG00030_20121012_1152.jpg

Thanks!

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 Destructive edit rolled back. – user53153 Mar 9 at 2:22 @5pm: How did you even come across this thread? – Asaf Karagila Mar 9 at 2:34 @AsafKaragila Bumped to the front page by Community (before I upvoted the answer to keep the bot quiet). – user53153 Mar 9 at 2:40 @5pm: Ah. If only these autobumps were documents... thanks. – Asaf Karagila Mar 9 at 2:41

$$\{x\}=\frac{1}{2}-\sum_{n=1}^N\frac{\sin 2\pi nx}{\pi n}+O((1+||x||N)^{-1}) = \frac{1}{2}-\sum_{n=1}^\infty\frac{\sin 2\pi nx}{\pi n}$$