How to express (a^2+b^2)^n,(n>1) in CVX?

I have a new question, the expression is like (a^2+b^2)^n ,where a and b are variables, n is a constant and n>1. can it be transformed into something like norm expression :face_with_raised_eyebrow: , I guess?

pow_pos(norm([a b]),2*n)

You would benefit from a careful reading of chapter 9 of the CVX Users’ Guide

Wow, I don’t know the pow_pos can perform convex^n,(n>1). :joy:

You need to look at help, as opposed to Users’ Guide, to see full usage rules.

help pow_pos

pow_pos Power of positive part.
pow_pos(X,P) = POS(X).^P = MAX(X,0).^P.
Both P and X must be real, and P must be greater than or equal to 1.

Disciplined convex programming information:
    pow_pos(X,P) is convex and nondecreasing in X; so when used in CVX
    expressions, X must be convex. P must be constant, real, and
    greater than or equal to 1.