How about that Cov(i,j) formula...

…on page 73 of Schweser Book 2. It seems every time I look at it, it changes slightly.

What’s is now?

What it really is about the simplest possible quadratic form. Which is why it wont be on the test. Because anybody who has thought about quadratic forms changes that in their head to something really easy to remember and that makes it an unfair question (if you have taken a linear algebra class, it’s just (b * sigma)^2 which is pretty easy to remember).