How to handle c*x/((x+a)*(x+b)) Nonconvex May 3, 2019 S mhy May 3, 2019 #1 x is a variable,and c,a,b are positive constants ,so how to handle cx/((x+a)(x+b)) into DCP ruleset? thanks! M Mark L. Stone May 3, 2019 #2 This is neither convex nor concave, except perhaps over ac certain range, depending on the values of a, b, c. For instance, if a = b = c = 1, then the 2nd derivative is negative for x < 2 and positive for x > 2.