/pi*y\ cos|----| \2*b /
cos((pi*y)/((2*b)))
Let .
The derivative of cosine is negative sine:
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*y\ -pi*sin|----| \2*b / -------------- 2*b
2 /pi*y\ -pi *cos|----| \2*b / --------------- 2 4*b
4 /pi*y\ pi *cos|----| \2*b / ------------- 4 16*b