C1 Topic 2: Algebra
Using graphs to solve equations
Equations like x2-2x-4 = 0 can be solved by plotting y = x2-2x-4 and seeing where the curve crosses the x axis. Solve these equations. Move the slider until y = o. Use your mouse to zoom in to increase accuracy. The left button zooms in; shift-click the lleft button to zoom out. Click and hold the right button to drag the graph left or right.

Summary A straight line and a quadratic curve can have 0, 1 or 2 points of intersection. Based on free Java applets from JavaMath