Don't know the steps in finding this derivative.
But the derivative is
The answer is:
cosh(x) /cosh(x) \
x *|------- + log(x)*sinh(x)|
\ x /
/ 2 \
cosh(x) |/cosh(x) \ cosh(x) 2*sinh(x)|
x *||------- + log(x)*sinh(x)| + cosh(x)*log(x) - ------- + ---------|
|\ x / 2 x |
\ x /
/ 3 \
cosh(x) |/cosh(x) \ 3*sinh(x) 2*cosh(x) 3*cosh(x) /cosh(x) \ / cosh(x) 2*sinh(x)\|
x *||------- + log(x)*sinh(x)| + log(x)*sinh(x) - --------- + --------- + --------- + 3*|------- + log(x)*sinh(x)|*|cosh(x)*log(x) - ------- + ---------||
|\ x / 2 3 x \ x / | 2 x ||
\ x x \ x //