1. The problem statement, all variables and given/known data Let F(AB) be the Frobenius-Norm in respect of the matrix A*B. And let ||A||2 be the operator norm. I have to show that F(AB)<=F(B)*||A||2 2. The attempt at a solution I wrote F(AB) in terms of sums and then tried to go on. But I don't know how I could include the necessary operator norm into the inequality.