Let .
The derivative of sine is cosine:
Then, apply the chain rule. Multiply by :
The derivative of a constant times a function is the constant times the derivative of the function.
Apply the power rule: goes to
So, the result is:
The result of the chain rule is:
The answer is:
/ 2 / 2\ / 2\\ 8*\- 8*x *sin\4*x / + cos\4*x //
/ / 2\ 2 / 2\\ -64*x*\3*sin\4*x / + 8*x *cos\4*x //