I want to find the energy efficiency, how to do it with CVX?P 1 and P 2 are variables, and the rest are constants。

I want to find the energy efficiency, how to do it with CVX?P 1 and P 2 are variables, and the rest are constants。

Let’s consider the special case in which P2 = 0, and is not a variable.
Then the expression is convex for x^2 \le \sigma^2, and concave for x^2 \ge \sigma^2. So it is neither convex nor concave.over the entirety of its domain…