Hi,

I'm for once attempting to do the practise questions for the subject but confused already just looking at it!

Anyone able to help with the following?

Show the following:

oo

x~ (2)[SUM ((-1)^(n-1))((sin nx)/n), -PI<x<PI

n=1

oo

x^2~ ((PI^2)/3)+ (4)[SUM ((-1)^n)((cos nx)/(n^2))]

n=1

I'm thinking the problems need the same method so if I could get a start on the first I might be able to figure out the second? It won't leave my oo and n=1 sign where I want them so they are supposed to go above and below the SUM if anyone is wondering