1. ## Is this question correctly asked?

Hey guys,

I just want to know if this question is missing an x after the (A^T A). Does the question given make sense?

2. ## Re: Is this question correctly asked?

$x^T (A^T A)$ is a $1\times n$ vector so saying

$x^T (A^T A) \geq 0$ doesn't make a whole lot of sense.

Yes, they probably mean $x^T(A^T A)x$