Trigonometric functions of α and −α
Answers are for parents and teachers.
1
Compute sin(−π/3).
−√3/2
2
Compute cos(−45°) − sin(−45°).
√2
3
Simplify tan(−α) · cos(−α).
−sin α
4
Simplify cot(−α) · tan α.
−1
5
Why is the graph of y = sin x symmetric about the origin?
sin(−x) = −sin x, i.e. sine is odd: together with (x, y) the point (−x, −y) lies on the graph.