I met a problem model like this:

min a + b

s.t. (c^3)/(a^2) + b <= constant

…

where a,b,c are variables,

I think the term (c^3)/(a^2) is convex, but I don’t know how to express it in cvx.

Can anyone help me with this?

I met a problem model like this:

min a + b

s.t. (c^3)/(a^2) + b <= constant

…

where a,b,c are variables,

I think the term (c^3)/(a^2) is convex, but I don’t know how to express it in cvx.

Can anyone help me with this?

Yes you have. Also note that x^3/y^2 is convex, but, contrary to the question title as you entered it before I added the moderator note to it, not affine.

Thank you very much, Mr.Mark.