Originally Posted by

**db5vry** A question on my practice exam paper says:

The curve C has equation y = 3x³ - 3x² - 9x + 2. Find the coordinates of the stationary points of C and determine the nature of these points.

I worked part out as:

dy/dx = 3x² - 6x - 9 = 0

(/3) = x² - 2x - 3 = 0

(x-3)(x+1) = 0

x = 3, x = -1

When x=3:

(3)³ - 3(3)² - 9(3) + 2

= 27 - 27 - 27 + 2

= -25

When x=-1:

(-1)³ - 3(-1)² - 9(-1) + 2

= -1 - 3 + 9 + 2

= 7

Coordinates are (3,-25),(-1,7).

Is this right so far and what do I need to do to complete the rest?