20*sin(x)*cos(x) ---------------- 3
d /20*sin(x)*cos(x)\ --|----------------| dx\ 3 /
The derivative of a constant times a function is the constant times the derivative of the function.
Apply the product rule:
; to find :
The derivative of cosine is negative sine:
; to find :
The derivative of sine is cosine:
The result is:
So, the result is:
Now simplify:
The answer is: