Question 170922
Solve the equation for x in the interval 0≤x ≤2 π: 
2sin²x-sinx-1=0

Factor to get:
(2sinx+1)(sinx-1) = 0

sinx = -1/2 or sinx = 1

x = (11/6)pi or (7/6)pi or pi/4 or (3/4)pi
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Cheers,
Stan H.