Hello everybody! I am new here and probably going to visit here pretty often in the future. Sometimes I do not get very clear answer from the lecturers so I hope to get more sensible answers from PF. 1. The problem statement, all variables and given/known data I need to show that x^y > y^x whenever y > x ≥ e. 3. The attempt at a solution At first I start by multiplying by ln(): y*ln(x) > x*ln(y) Then I take g(x,y) such that g(x,y) = y*ln(x) - x*ln(y) and 2nd order derivatives and show det(H(g)) < 0 whenever y > x ≥ e My purpose with this is to show that there are no real local or global critical points in g(x,y) when y > x >= e, and conclude that g(x) = x^y - y^x diverges. I was not told why I can not use Hessian determinant to make this conclusion. Why I can not use Hessian approach to prove this? What would be the correct way to do it? Can I prove it with induction?