I can't seem to derive this results that my book "Linear Algebra Done right" is using without explanation. It must be obvious but I don't see it.
Let $T$ be a self adjoint operator. How do they go from $ <T^2(v), v> = <Tv, Tv> $ I know $T^2=T^*T $ however I still don't see the jump from $<T^*T(v),v>$ to $<Tv,Tv>$
Also usually when I read questions/answers with operators and the like they mention Hilbert spaces, but I haven't learned about those at all.