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If 4 - 2sin2θ - 5cosθ = 0, 0° < θ < 90°, then the value of sinθ + tanθ is:
Answer & Solution
Correct Answer:
Option
B
$$\eqalign{
& 4 - 2{\sin ^2}\theta - 5\cos \theta = 0 \cr
& {\text{Let }}\theta = {60^ \circ } \cr
& 4 - 2{\sin ^2}{60^ \circ } - 5\cos {60^ \circ } = 0 \cr
& 4 - 2 \times \frac{3}{4} - 5 \times \frac{1}{2} = 0 \cr
& 4 - 4 = 0 \cr
& \sin \theta + \tan \theta = \sin {60^ \circ } + \tan {60^ \circ } \cr
& = \frac{{\sqrt 3 }}{2} + \sqrt 3 \cr
& = \frac{{3\sqrt 3 }}{2} \cr} $$
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