Let .
The derivative of is .
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 the constant is zero.
The result is:
The result of the chain rule is:
Now simplify:
The answer is:
/ 2 \
| 18*x |
18*|1 - --------|
| 2|
\ 2 + 9*x /
-----------------
2
2 + 9*x
/ 2 \
| 12*x |
972*x*|-1 + --------|
| 2|
\ 2 + 9*x /
---------------------
2
/ 2\
\2 + 9*x /