1. A method for determining a price that maximizes revenue comprising: providing a demand curve; calculating a first angle, said first angle calculated by determining the angle between a first reference line and a second reference line; calculating a second angle, said second angle calculated by determining the angle between said first reference line and a line running tangent to said demand curve at said price; determining whether said first angle is equal to said second angle; and changing said price and calculating said first angle, calculating said second angle, and determining whether said first angle is equal to said second angle until a price is found at which said first angle is equal to said second angle.