3 cos (x)*x
cos(x)^3*x
3 2 cos (x) - 3*x*cos (x)*sin(x)
/ / 2 2 \ \ 3*\x*\- cos (x) + 2*sin (x)/ - 2*cos(x)*sin(x)/*cos(x)
/ / 2 2 \ / 2 2 \ \ 3*\3*\- cos (x) + 2*sin (x)/*cos(x) - x*\- 7*cos (x) + 2*sin (x)/*sin(x)/