hi everyone. first of all i have to apologize for my poor English.
I've got an inequality which I know is true but don't know how to solve,can anyone help?
That isn't an inequality.
Let's consider the functions , .
is strictly increasing;
is strictly decreasing, so is strictly increasing;
is strictly increasing (being a sum of two strictly increasing functions) f is injective, and therefore .
, for any f is injective, and therefore .