trig
posted by Wes on .
How do you express in terms of angles less than 90 degrees?
sin 120 degrees
cos 150 degrees
tan 280 degrees

Always ask yourself,
1. What quadrant is the angle in? That determines the ± according to the CAST rul
2. "How far is it to the xaxis"?
sin 120° = sin60
cos150° = cos 30
tan 280° = tan 80° 
Sin (180  A) = sin A. (angle in degrees)
sin 120 = sin (180  60) = sin 60
Cos (180  A) =  cos A
cos 150 = cos (180  30) =  cos 30
tan (360  A) =  tan A,
tan 280 = tan (360  80) =  tan 80