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