Finding the sum of a Fourier series from part 2

[VooDoo]

hey guys,

I got this question that I am a bit stuck on. I have done question two and got the Fourier series, but have no idea how to do part 3. Any help is very appreciated.
http://img453.imageshack.us/img453/5103/file2yp2.jpg

 

[cristo]

What did you get for exercise 2? That will probably be quite useful information for solving 3!

 

[VooDoo]

Hi, I got the following for my Fourier series. I have a 1/n^2 term in there which looks good.
http://img392.imageshack.us/img392/5124/11111je7.jpg

 

[Eighty]

Choose an appropriate x.