Touba M. answered 12/06/21
Tutor
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College Math Faculty 20+ Years- SAT, Calculus &Trigonometry Expert
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