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