Touba M. answered 12/06/21
Tutor
4.9
(31)
B.S. in Pure Math with 20+ Years Teaching/Tutoring Experience
hi,
Apparently, you need to know how solve equation in trig.
In fact, the method is the same of algebra, only need to know all information about 30, 45, 60
2sinθ −1=0
2sinθ −1 +1=0 +1 ===> sinθ = 1/2 = sin 30
θ = {30 , 150} check unit circle!
I hope it is useful,
Minoo