1. Double-Angle, Half-Angle Formulas

2. Double-Angle Formulas
Formula for sine: Formula for cosine: Formula for tangent:

3. Ex 1. If and x is in quadrant II, find cos 2x, sin 2x, and tan 2x.

4. Ex 2. If and x is in quadrant I, then find sin 2x, cos 2x, and tan 2x.

5. Class Work
3. If and x is in quadrant II, find sin 2x, cos 2x, and tan 2x.

6. Half-Angle Formulas

7. Ex 3. Find the exact value of sin 22.5.

8. Ex 4. Find

9. Ex 5. Find if and u is in quad II.

10. Find if and u is in quad IV.