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.
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:
So, the result is:
The result of the chain rule is:
Now simplify:
The answer is:
/pi*x\
pi*cos|----|
\ 2 /
------------
2
2 /pi*x\
-pi *sin|----|
\ 2 /
---------------
4
3 /pi*x\
-pi *cos|----|
\ 2 /
---------------
8