How do i find the critical points?

intervals: [ -1, 2]

Critical points is where the derivative (slope) is zero or does not exist. So to do this we have to find the derivative of our function:



So we apply chain rule:

= 

Set our first derivative to zero and solve for x:

3(x^2 - 1) * 2x = 0

So we can see that (by plugging in) 0, -1 and 1 makes our solution true

So our critical value is x = 0, x = -1, x = 1