Arthur D. answered 12/11/17
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let x=θ
2sin^2x=sinx+1
2sin^2x-sinx-1=0
factor
(2sinx+1)(sinx-1)=0
2sinx+1=0
2sinx=-1
sinx=-1/2
look on the unit circle
sin is -1/2 when x=7∏/6 or 210º (+∏k where k=0,±1,±2,...)
sinx-1=0
sinx=1
sin is 1 when x=∏/2 or 90º (+∏k where k=0,±1,±2,...)