This dynamic diagram illustrates the three main trig functions -- sine, cosine and tangent -- along with their reciprocals -- cosecant, secant and cotangent. Note that the tangent and cotangent are actually lines tangent to the circle. [br][br]The secant and cosecant cut through the curve, which is what secant lines do. And the sine and cosine -- well, those are based on mistranslations from Sanskrit through Arabic through Latin to English.[br][br]Grab the blue ring with your mouse (or finger, if you have a touch pad) and drag it around the circle. Observe how each of these elements waxes and wanes as the angle changes.