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The value of  2−sin2⁡α1−cos⁡α+1−cos⁡αsin⁡α−sin⁡α1+cos⁡α2-\frac{sin^2⁡α}{1-cos⁡α }+\frac{1-cos⁡α}{sin⁡α} -\frac{sin⁡ α}{1+cos⁡α }2−1−cos⁡αsin
Question

The value of  2sin2α1cosα+1cosαsinαsinα1+cosα2-\frac{sin^2⁡α}{1-cos⁡α }+\frac{1-cos⁡α}{sin⁡α} -\frac{sin⁡ α}{1+cos⁡α }​ is

A.

1-sin⁡α

B.

1-cos⁡α

C.

1+sin⁡α

D.

1+cos⁡α

Correct option is B

Given:

2sin2α1cosα+1cosαsinαsinα1+cosα2-\frac{sin^2⁡α}{1-cos⁡α }+\frac{1-cos⁡α}{sin⁡α} -\frac{sin⁡ α}{1+cos⁡α } 

Concept Used: 

sin2θ+cos2θ=1  1cos2θ=sin2θ  (1cosθ)(1+cosθ)=sin2θ\sin^2 \theta + \cos^2 \theta = 1 \\ \ \\ \implies 1 - \cos^2 \theta = \sin^2 \theta \\ \ \\ \implies (1-\cos \theta)(1+\cos \theta) = \sin^2 \theta  

Solution: 

2sin2α1cosα+1cosαsinαsinα1+cosα =21cos2α1cosα+(1cosα)(1+cosα)sin2αsinα(1+cosα) =2(1cosα)(1+cosα)1cosα+(1cos2α)sin2αsinα(1+cosα) =2(1+cosα)+sin2αsin2αsinα(1+cosα) =2(1+cosα)+0sinα(1+cosα) =21cosα =1cosα2-\frac{sin^2⁡α}{1-cos⁡α }+\frac{1-cos⁡α}{sin⁡α} -\frac{sin⁡ α}{1+cos⁡α } \\ \ \\ = 2-\frac{1 - cos^2⁡α}{1-cos⁡α }+\frac{(1-cos⁡α)(1+cos⁡α)- sin^2α }{sin⁡ α(1+cos⁡α) }\\ \ \\ = 2-\frac{(1 - cos⁡α)(1 + cos⁡α)}{1-cos⁡α }+\frac{(1-cos⁡^2α)- sin^2α }{sin⁡ α(1+cos⁡α) }\\ \ \\ = 2-(1 + cos⁡α)+\frac{sin^2α - sin^2α }{sin⁡ α(1+cos⁡α) }\\ \ \\ = 2-(1 + cos⁡α)+\frac{0 }{sin⁡ α(1+cos⁡α) } \\ \ \\ = 2 - 1 - cos⁡α \\ \ \\ = 1 - cos⁡α​​

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