http://i45.tinypic.com/r9lfg5.jpg
i found a_n b_n a_0
but i need to replace the sines
like (-1)^n=cos(pi*n)
i dont know how to do it which sines
http://i45.tinypic.com/r9lfg5.jpg
i found a_n b_n a_0
but i need to replace the sines
like (-1)^n=cos(pi*n)
i dont know how to do it which sines