Let .
The derivative of cosine is negative sine:
Then, apply the chain rule. Multiply by :
Let .
The derivative of is itself.
Then, apply the chain rule. Multiply by :
Differentiate term by term:
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 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 is:
The result of the chain rule is:
The result of the chain rule is:
Now simplify:
The answer is:
/ 2 / x*(2 - x)\ 2 / x*(2 - x)\ x*(2 - x) / x*(2 - x)\\ x*(2 - x) 2*\- 2*(-1 + x) *sin\e / - 2*(-1 + x) *cos\e /*e + sin\e //*e