A third class of functions that are prevalent
in higher mathematics is the trigonometric functions. For a full discussion
of trigonometry, see the SparkNote on Trigonometry. In the following
lessons, we'll take a brief look at the trigonometric functions. The
trigonometric functions have to do with angles in the coordinate plane. They
are unique because the input is an angle measure, and the output is a ratio.
The six trigonometric functions are sine, cosine, tangent,
cosecant, secant, and cotangent. They are periodic
functions--their values repeat at regular
intervals. The sine and cosine functions are especially useful in modeling
repetitive motion, like oscillation. Sine and cosine can also be thought of as
the most important of the trigonometric functions because of their relevance to
the unit circle and the fact that the other four trigonometric functions can
easily be expressed in terms of sine and cosine. In addition to examining the
trigonometric functions and their graphs, we'll discuss the inverse
trignometric functions and also some trigonometric equations.