# Autonomous ODE?

1. Feb 2, 2012

### MathWarrior

The problem for this is a picture. Its basically a U shaped parabola such that it intersects the points (-3,0) (0,0) (3, 0)

you have a graph such as:

f(x)
|
|
|------- y
|
|

The problem I am having is this.. I know what it means when a point is unstable or stable we tended to draw arrows on either side of the phase lines. I am unsure of how you figure out which way the arrow goes basically, I think it has something to do with their derivative but how am I suppose to find the derivative of a visual graph without an equation?