I have verify that a*x_k /( b - c*x_k) is a convex function, where a,b,c are constants. It is used in the constraint function as follows:

\sum_{k=1}^{K} a*x_k /( b - c*x_k) <=E, where E is a constant.

I have tried to transform it into a /( b/x_k - c), but it doesn’t work.

How can CVX identify this convex function?

Thanks for your kind help!