# At where f(x)=|(x^2)-9| is differentiable?

##### 1 Answer

Jan 27, 2016

Everywhere except x=3 and x=-3

#### Explanation:

Since

Now we must calculate derivates at the points

If

If

When

The values are different, therefore f(x) is not differentiable in x=3.

The same conclusion could be obtained when x=-3.