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) * [tex]\Sigma[/tex] (-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!