Addition formulas
Answers are for parents and teachers.
1
Compute sin 15° = sin(45° − 30°).
(√6 − √2)/4
2
Compute cos 15° cos 75° − sin 15° sin 75°.
0
3
If sin α = 5/13 and cos β = 3/5 (both angles in quadrant I), find sin(α + β).
63/65
4
If tan α = 2 and tan β = 3, find tan(α + β).
−1
5
Prove that sin(α + β) + sin(α − β) = 2 sin α cos β.
(sin α cos β + cos α sin β) + (sin α cos β − cos α sin β) = 2 sin α cos β.