Is x/log(1+x) concave? If yes? How can I use cvx solve the constraints " x/log(1+x) >= C", where C is constant.
Presuming x >= 0, that would be x >= log(1+x)*C, which is a non-convex constraint if C > 0, and is a convex constraint if C < 0.
You should be coming to us with a convex constraint, which you have proven to be convex, not asking us whether it is convex.
Yes, when x>0, it’s cocave. Expressing it is equivalent to Expressing the following
Received with thanks.
WoW! That is a great idea. Thank you~