Sketching Cubics

In this video you will learn how to sketch a cubic graph. First of all make sure the cubic equation is factorised. This will let you work out where the graph intersects the x axis. If you have 3 different solutions then the cubic will cross the x-axis 3 times. If the root is repeated then the graph will just touch the x-axis at this point but not pass through it. A positive x cubed graph will start in the bottom left of the coordinate grid, and a negative x cubed graph will start from the top left of the grid.