Question

I guess I'm not understanding the concept for part of this, what should I know?

I'm posting my answers below, I would like to know what I did incorrectly in the middle part.
Yes I realize this is about identifying concavity and how to do that, but I want to know how to do the notation as shown, what that means I need to do mathematically, in steps.

I'll be back tomorrow to check on this :-)

Answer 1

So to find the second derivative of a parametric, I need to do what in what order, basically. The textbook is kind of a fail on this explaining this part and it's not covered in the lecture.