We started by looking at homework which used the double angle formula.

The basic approach was to do two things, could start in either order.

1. Draw the angle with a right triangle on the xy axes.

2. Use a double angle formula which is convenient

You can figure out the ratios for the trig functions using

SOHCAHTOA

CHOSHACAO

Then looked at a previous test with graphing trig functions. Should spend more time on that. But one thing you can do most of the time is plot points by plugging in x values and getting y values. You use again,

SOHCAHTOA

CHOSHACAO

It does help quite a bit to know the basic shape of the functions.