Proving Matrix Norm Inequality for Frobenius-Norm and Operator Norm

[Kruger]

Homework Statement

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.

 

[Kruger]

Mhhh, isn't there anyone that can help me?

 

[HallsofIvy]

You say you "tried to go on" but haven't shown anything at all of what you actually did. You might start by defining "Frobenius Norm" and "operator norm". How are thy related.