The page demonstrates how the function [math]sec[/math] is related to the [b]unit circle[/b] used by many mathematicians to explain the functions [math]sin, cos[/math] and [math]tan[/math].
It also extends to provide an argument for the trigonometric (pythagorean) identity:
[math]sec2(x) = tan2(x) + 1[/math]
This identifies the right angled triangle that is needed, and often ignored by teachers (resorting to simple statement divide by cos2(x)).
