As easily seen by looking at the 2nd derivative, for c = 2, it is convex for 0 < x < exp(5/6), and concave for x > exp(5/6). So your thinking is incorrect.
Please read Why isn't CVX accepting my model? READ THIS FIRST!
As easily seen by looking at the 2nd derivative, for c = 2, it is convex for 0 < x < exp(5/6), and concave for x > exp(5/6). So your thinking is incorrect.
Please read Why isn't CVX accepting my model? READ THIS FIRST!