Definitions of the Trig Functions

In order to shorten some of the writing, we will use the abbreviations ``opp'' for opposite side, ``adj'' for adjacent side, and ``hyp'' for hypotenuse. Then we have the following definitions:

Note that the functions in question are actually abbreviated by , , , , , and . The functions are actually called ``sine'', ``cosine'', ``tangent'', ``cotangent'', ``secant'', and ``cosecant''. (Notice that there are 3 ``co''-functions which seem to correspond to the other three functions. It is interesting that the names exhibit such a relationship.)

I cannot emphasize the importance of knowing the definitions of these six functions! You must be able to quickly identify the appropriate ratio for each function, so I encourage you to spend time learning these, even if that simply means spending time memorizing them.