Originally Posted by

**gva0324** Hello, I need help deriving this and finding the stationary points for the following:

$\displaystyle y= 3x / (x^2 + 1)$

If somebody could please show me the method of how to do this. I compared my answer with the result in a calculator and I do not know what I am doing wrong.

Hi **gva0324**.

Use the quotient rule:

$\displaystyle \mbox{If}\ y=\frac uv,\ \frac{dy}{dx}=\frac{v\dfrac{du}{dx}-u\dfrac{dv}{dx}}{v^2}$

The stationary points are where $\displaystyle \frac{dy}{dx}=0.$