Find the stationary points of y=x^3 + 3x^2 - 9x - 4

The stationary points of the function are the points at which the gradient is equal to 0. (If you draw out a standard y=x^3 graph, you can see the gradient is 0 at the points where the graph changes direction)1) Differentiate the expression to find the gradient2) Set this differential equation to equal 0, as this will give you the points at which the gradient is equal to 03) Find the roots of the equation by factorizing4) Substitute each of the roots found in place of 'x' in to the original equation for the graph, to find the corresponding y values.