if 2sin2θ + 3sin θ - 2 = 0, (0 > θ > 90° ) then the value of θ is :
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Correct answer: B
Explanation
The correct answer is option 2 i.e. 30°.
Given that, 2sin2θ + 3sinθ - 2 = 0
⇒ 2sin2θ + 4sinθ - sinθ - 2 = 0
⇒ 2sinθ(sinθ + 2) - 1(sinθ + 2) = 0
⇒ (2sinθ - 1)(sinθ + 2) = 0
sinθ = 1/2; sinθ = -2 (Not possible)
⇒ sinθ = 1/2
⇒ θ = 30°