Answer:
Let x=sinθ
2sin²θ = 5sinθ - 3
2x²=5x-3
2x²-5x+3=0
(2x-3)(x-1)=0
2x-3=0 or x-1=0
x=3/2 or x=1
sinθ=2/3 or sinθ=1
θ=arcsin(2/3) or θ=arcsin(1)
θ=0.729727656 or θ=1.57079633=π/2
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