Originally Posted by

**halfnormalled** Hello, I did a forum search and I think this is the correct place to post this. There seem to be a lot of other posts in here on this topic. The question is this:

Find the complex Fourier series of the sawtooth wave

$\displaystyle f(t) = t, 0<t<1$ and where $\displaystyle f(t+1) = f(t)$

So, I'm trying to use the equation:

$\displaystyle f(t) = \sum_{-\infty}^{\infty} c_n e^{jnwt}$

where

$\displaystyle c_n = \frac{1}{T} \sum_{-\frac{T}{2}}^{\frac{T}{2}} f(t) e^{-jnwt} \,dt$

But I'm not getting the answer I'm expecting. I'm not sure what the limits of the integral should be. As the function is not defined for t<0, can I just put:

$\displaystyle c_n = \frac{1}{T} \sum_{0}^{1} te^{-jnwt} \,dt$

Or do I need to do something to balance out the fact that the equation doesn't run across the origin...? I'm confused....

Thanks very much in advance.