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If 7sin2θ + 3cos2θ = 4, then the value of secθ + cosecθ is?

A. $$\frac{2}{{\sqrt 3 }} - 2$$

B. $$\frac{2}{{\sqrt 3 }} + 2$$

C. $$\frac{2}{{\sqrt 3 }}$$

D. None of these

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & {\text{7}}{\sin ^2}\theta + 3{\text{co}}{{\text{s}}^2}\theta = 4 \cr & {\text{7}}{\sin ^2}\theta + 3\left( {{\text{1}} - {\text{si}}{{\text{n}}^2}\theta } \right) = 4 \cr & {\text{7}}{\sin ^2}\theta + 3 - 3{\sin ^2}\theta = 4 \cr & 4{\sin ^2}\theta = 1 \cr & {\sin ^2}\theta = \frac{1}{4} \cr & {\text{sin }}\theta = \frac{1}{2} \cr & \sin \theta = \sin {30^ \circ } \cr & \theta = {30^ \circ } \cr & \sec \theta + \operatorname{cosec} \theta \cr & = \sec {30^ \circ } + \operatorname{cosec} {30^ \circ } \cr & = \frac{2}{{\sqrt 3 }} + 2 \cr} $$

This Question Belongs to Arithmetic Ability >> Trigonometry

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