Evaluating a fourier series using the firs 100terms

1. Aug 23, 2009

paul143

Well, the problem gave me a symmetric square wave f(x).

f(x) = 1, when |x|<pi/2 and -1, pi/2 < |x|< pi

I was able to solve for its fourier series expansion given by:

f(x) = (4/pi) * $$\Sigma$$ (-1)n cos(2n+1)x / 2n+1

Now the problem asked us to evaluate this series for x=0(pi/18)pi/2 using the first 100terms of the series.

Now this is where i was really stuck, i can't seem to grasp the meaning of "from x=0(pi/18)pi/2". I'm not familiar with this notation. Can anyone enlighten me please?

And if possible, point me in the right direction in evaluating this series thanks so much!

2. Aug 23, 2009

maverick280857

Welcome to PF!

You have to take the first 100 terms, sum them up, call it some function S(x), and then find values of S(x) from x = 0 to x = pi/2, in steps of pi/18 (which is what the notation means).

Last edited: Aug 23, 2009
3. Aug 23, 2009

paul143

ooohhh!!! i seee!! thanks very much!! :D now i understand :D