When you subtract theta from 180 ( if theta is between 90 degrees and 180 degrees) you will get the reference angle of theta; the results of sine theta and sine of its reference angle will be the same and only the sign will be different depends on which quadrant the angle is located.
Ex. 150 degrees' reference angle will be 30 degrees (180-150)
sin150=1/2 (2nd quadrant); sin30=1/2 (1st quadrant)
1st quadrant: all trig functions are positive
2nd: sine and csc are positive
3rd: tangent and cot are positive
4th: cosine and secant are positive
Copyright © 2026 eLLeNow.com All Rights Reserved.
