How do you evaluate #cos150#?
1 Answer
May 25, 2016
Explanation:
First method
Trig table, unit circle, and property of complementary arcs -->
Second method:
Use trig identity: cos (a + b) = cos a.cos b - sin a.sin b
cos (150) = cos (60 + 90) = cos 60.cos 90 - sin 60.sin 90 =
= - sin 60 =
Note.