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sinθ1+cosθ+1+cosθsinθ=?\frac{\sin \theta}{1+\cos \theta}+\frac{1+\cos \theta}{\sin \theta}=?

a

2 sin θ

b

2 cos θ

c

2 sec θ

d

2 cosec θ

Answer : Option D
Explanation :

sinθ1+cosθ+1+cosθsinθ=sin2θ+(1+cosθ)2(1+cosθ)sinθ\frac{\sin \theta}{1+\cos \theta}+\frac{1+\cos \theta}{\sin \theta}=\frac{\sin ^{2} \theta+(1+\cos \theta)^{2}}{(1+\cos \theta) \sin \theta}

=sin2θ+1+2cosθ+cos2θ(1+cosθ)sinθ=\frac{\sin ^{2} \theta+1+2 \cos \theta+\cos ^{2} \theta}{(1+\cos \theta) \sin \theta}

=sin2θ+cos2θ+1+2cosθ(1+cosθ)sinθ=2+2cosθ(1+cosθ)sinθ=\frac{\sin ^{2} \theta+\cos ^{2} \theta+1+2 \cos \theta}{(1+\cos \theta) \sin \theta}=\frac{2+2 \cos \theta}{(1+\cos \theta) \sin \theta}

=2(1+cosθ)(1+cosθ)sinθ=2sinθ=\frac{2(1+\cos \theta)}{(1+\cos \theta) \sin \theta}=\frac{2}{\sin \theta}

= 2 cosec θ

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