The Fourier Cosine series of the function f(x)=3-x, 0<x<3 is a) f(x)=3+ 2 00 b) f(x)=Σ n=1 3 c) f (x) = + d) f(x) 2 3 == 2 + 6 π 1- cos(nл) n² 1- cos(nл) 00 n² ηπ COS 3 ηπ COS 3 1- cos(nл) 00 6 n=1 n² ηπ COS X 3 ηπ COS 3 1-cos (nл) n²