If 7sin2θ + 4cos2θ = 5 and θ lies in the first quadrant, then what is the value of $$\frac{{\sqrt 3 \sec \theta + \tan \theta }}{{\sqrt 2 \cot \theta - \sqrt 3 \cos \theta }}?$$
A. 3√2
B. 2(1 + √2)
C. 4√2
D. 2(√2 - 1)
Answer: Option B
Solution(By Examveda Team)
$$\eqalign{ & 7{\sin ^2}\theta + 4{\cos ^2}\theta = 5 \cr & 3{\sin ^2}\theta + 4{\sin ^2}\theta + 4{\cos ^2}\theta = 5 \cr & 3{\sin ^2}\theta + 4 = 5 \cr & 3{\sin ^2}\theta = 5 - 4 \cr & 3{\sin ^2}\theta = 1 \cr & {\sin ^2}\theta = \frac{1}{3} \cr & \sin \theta = \frac{1}{{\sqrt 3 }} = \frac{P}{H} \cr & B = \sqrt {{{\left( {\sqrt 3 } \right)}^2} - {1^2}} = \sqrt 2 \cr & \Rightarrow \frac{{\sqrt 3 \sec \theta + \tan \theta }}{{\sqrt 2 \cot \theta - \sqrt 3 \cos \theta }} \cr & = \frac{{\sqrt 3 \times \frac{{\sqrt 3 }}{{\sqrt 2 }} + \frac{1}{{\sqrt 2 }}}}{{\sqrt 2 \times \frac{{\sqrt 2 }}{1} - \sqrt 3 \times \frac{{\sqrt 2 }}{{\sqrt 3 }}}} \cr & = \frac{{\frac{4}{{\sqrt 2 }}}}{{2 - \sqrt 2 }} \cr & = \frac{{2\sqrt 2 }}{{2 - \sqrt 2 }} \cr & = \frac{{2\sqrt 2 }}{{2 - \sqrt 2 }} \times \frac{{2 + \sqrt 2 }}{{2 + \sqrt 2 }} \cr & = \frac{{2\sqrt 2 \left( {2 + \sqrt 2 } \right)}}{{4 - 2}} \cr & = 2\left( {\sqrt 2 + 1} \right) \cr} $$Related Questions on Trigonometry
A. x = -y
B. x > y
C. x = y
D. x < y
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