Let V be an inner product space over field C(complex numbers). dim(V)<inf,

T:V-->V linear transformation.

1. Prove that T is normal (T*T=T*T) iff there exist polynomial p(x) in C[x] so that T*=p(T)

2. Conclude that if T,S:V-->V linear transformations, T normal and TS=ST, so T*S=S*T

Thank you all...