Show that the function `e^x/x^p` is strictly increasing for `x gt p gt 0`.

Explanation

Let `f(x) = e^x/x^p`
Then ``f.(x) = (e^x cdot x^p - e^x cdot px^p-1)/(x^2p)`
The function is increasing if f. `(x) gt 0`
`rArr (e^x cdot x^p - e^x cdot px^p-1)/(x^2p)gt 0`
`(e^x cdot x^(p-1) cdot (x-p) gt 0 rArr x gt p.