1. Find values for sin 2 and cos 2 if cos = and sin = .
2. Use a half-angle formula to find the exact value of sin 22.5°.
3. Find sin and cos if is acute. Use a calculator to support your results.
4. Verify that = 2 - sec2 .
5. Solve sin 2 = 2 cos for . Support your results graphically or numerically.
and cos 2
and sin 
.
and cos 
= 2 - sec2 
. Support your results graphically or numerically.