How to express x/(x+y) in cvx?

hello,I found that I could not express x/(x+y) right in cvx,it always got error,this function is just a subject in my project,how can I solve this problem?Thanks

This is a linear-fractional form.You can read about that and linear-fractional programming in https://web.stanford.edu/~boyd/cvxbook/bv_cvxbook.pdf .

Have you carefully read the link I posted in reply to your previous question How To express log(1+(x/(1+y)))? it’s not obvious to me that you have.

Thank you very much . I have read that link but didnt read it carefully , i will read again . Thanks again for taking time to answer my question，it helps me a lot!