Trig Functions Related to Unit Circle
- Mike Day
How are the trig functions related to a unit circle? Move point C or hit the play button in the bottom left hand corner to see what happens. The sin function is the height. Remember the word SHY. (S)in (H)eight (Y)-value. The cos function is the length. Remember CLX. That doesn't work very well, so remember SHY. Notice how the trig function can get to infinity. We made the distances positive, but remember the directions can be negative.
Why does the tangent function become empty when the angle is 90 degrees? What sign are the functions in each quadrant?