# The Cos and Sin functions

The picture to the left is very important. You can read off the values
of sin(x) = opposite side/hypothenuse, cos(x) = adjacent side/hypothenuse.
as well as tan(x) = opposite side/adjacent side, which is the slope.
Here are the formulas you need to know
sinExhibit of 2011 with animation | ||

Additionally, we need to know the following two triangles. |