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Find the value of sin⁡268∘+sin⁡222∘2(cos⁡217∘+cos⁡273∘)\frac{\sin^2{68^\circ} + \sin^2{22^\circ}}{2 \left( \cos^2{17^\circ} + \cos^2{73^\circ} \r
Question

Find the value of sin268+sin2222(cos217+cos273)\frac{\sin^2{68^\circ} + \sin^2{22^\circ}}{2 \left( \cos^2{17^\circ} + \cos^2{73^\circ} \right)}.

A.

–1

B.

0

C.

1

D.

12\frac{1}{2}

Correct option is D

Given: 

sin268+sin2222(cos217+cos273)\frac{\sin^2{68^\circ} + \sin^2{22^\circ}}{2 \left( \cos^2{17^\circ} + \cos^2{73^\circ} \right)} 

Formula Used: ​

sin(90θ)=cosθ cos(90θ)=sinθ sin2θ+cos2θ=1\sin(90 -\theta) = \cos \theta\\ \ \\ \cos(90 -\theta) = \sin \theta \\ \ \\ \sin^2\theta +\cos^2\theta = 1

Solution:

sin268+sin2222(cos217+cos273) =sin268+sin2(9068)2[cos2(9073)+cos273] =sin268+cos2682[sin273+cos273] =12\frac{\sin^2{68^\circ} + \sin^2{22^\circ}}{2 \left( \cos^2{17^\circ} + \cos^2{73^\circ} \right)}\\ \ \\ = \frac{\sin^2{68^\circ} + \sin^2{(90 -68)^\circ}}{2 \left[ \cos^2{(90-73)^\circ} + \cos^2{73^\circ} \right]} \\ \ \\ = \frac{\sin^2{68^\circ} + \cos^2{68^\circ}}{2 \left[ \sin^2{73^\circ} + \cos^2{73^\circ} \right]}\\ \ \\ = \frac{1}{2}​​

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