# What is the second derivative of #f(x)=x/(x^2 + 1) ^2#?

##### 1 Answer

Dec 26, 2015

#### Explanation:

Use the quotient rule: for a function

Thus,

Simplify.

**First Derivative**

To find the second derivative, use the quotient rule again.

Thus,

Simplify.

**Second Derivative**

The main two pitfalls here are

- algebra
- remembering to use the chain rule when differentiating things like
# (x^2+1)^2#