Homework Statement
Axler's Linear Algebra done right, propositions 7.6 states:
An operator T is normal if and only if ||Tv|| = || T*v||, T* being the adjoint of T.
I've been stuck on the last equivalence in the proof stated here:
<T*Tv,v>=<TT*v> <=> ||Tv||^2=||T*v||^2, with squaring...