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The value of     ​sin⁡210∘+sin⁡220∘+sin⁡230∘+sin⁡240∘+sin⁡250∘+sin⁡260∘+sin⁡270∘+sin⁡280∘+sin⁡290∘cos⁡220∘+cos⁡240∘+cos⁡250∘+cos⁡270∘+c
Question

The value of     ​sin210+sin220+sin230+sin240+sin250+sin260+sin270+sin280+sin290cos220+cos240+cos250+cos270+cos245\frac{\sin^2{10^\circ} + \sin^2{20^\circ} + \sin^2{30^\circ} + \sin^2{40^\circ} + \sin^2{50^\circ} + \sin^2{60^\circ} + \sin^2{70^\circ} + \sin^2{80^\circ} + \sin^2{90^\circ}}{\cos^2{20^\circ} + \cos^2{40^\circ} + \cos^2{50^\circ} + \cos^2{70^\circ} + \cos^2{45^\circ}} is ?

​​

A.

3/4

B.

5/3

C.

2

D.

4/3

Correct option is C

Given:  

sin210+sin220+sin230+sin240+sin250+sin260+sin270+sin280+sin290cos220+cos240+cos250+cos270+cos245\frac{\sin^2{10^\circ} + \sin^2{20^\circ} + \sin^2{30^\circ} + \sin^2{40^\circ} + \sin^2{50^\circ} + \sin^2{60^\circ} + \sin^2{70^\circ} + \sin^2{80^\circ} + \sin^2{90^\circ}}{\cos^2{20^\circ} + \cos^2{40^\circ} + \cos^2{50^\circ} + \cos^2{70^\circ} + \cos^2{45^\circ}}

Identity Used:

sin2θ+sin2(90θ)=1\sin^2{\theta} + \sin^2{(90^\circ - \theta)} = 1 

:cos2θ+cos2(90θ)=1: \cos^2{\theta} + \cos^2{(90^\circ - \theta)} = 1​​​

Solution:

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