Hello,

A few remarks, while I'm trying to solve it.

False. It's

It's correct :I consider . Now if we have a function then

(Is it correct and why)

since f is increasing, and by Markov's inequality, this is

But you're asked for in the RHS, there is no absolute value.Now if is strictly increasing function then

So I obtained:

Although since f is even, .

P.S. : Are you French ?