When , it implies we have a stationary point.

To determine the nature of the stationary point, we can do either the first derivative test **or** the second derivative.

The first derivative test:

Students should write the actual values of and in the table.

We use this under these two situations:

1. is difficult to solve for, that is, is tough to be differentiated

2.

The second derivative test:

Other things students should take note is concavity and drawing of the derivative graph.