Math, asked by singhmanoj8265, 2 months ago

cos0-sin0+1/cos0+sin0+1=cot0+cosec0​

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Answered by abhi5290
8

The answer is proved above in the image

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Answered by mathdude500
1

\large\underline{\bold{Given \:Question - }}

The Correct Statement is

 \sf \: Prove  \: that  \: \dfrac{cos \theta \: - sin\theta \: + 1 }{cos\theta \: + sin\theta \:  -  1}  = cosec\theta \: + cot\theta \:

\large\underline{\bold{Solution-}}

Identities Used :-

  1. \:  \:  \: \boxed{ \bf{cot\theta \: = \dfrac{cos\theta \:}{sin\theta \:} }}

  2. \:  \:  \: \boxed{ \bf{cosec\theta \: = \dfrac{1}{sin\theta \:} }}

  3. \:  \:  \: \boxed{ \bf{ {cosec}^{2}\theta \: -  {cot}^{2}\theta \: = 1}}

  4. \:  \:  \: \boxed{ \bf{ {x}^{2} -  {y}^{2}  = (x + y)(x - y)}}

Lets do the problem now!!

 \bf \: Consider  \: LHS -

 \sf \: \dfrac{cos\theta \: - sin\theta \: + 1}{cos\theta \: + sin\theta \:  -  1}

Divide numerator and denominator by sinθ, w get

 \sf \:  =  \: \dfrac{\dfrac{cos\theta \:}{sin\theta \:}  - \dfrac{sin\theta \:}{sin\theta \:}  + \dfrac{1}{sin\theta \:} }{\dfrac{cos\theta \:}{sin\theta \:}  + \dfrac{sin\theta \:}{sin\theta \:}  -  \: \dfrac{1}{sin\theta \:}  }

 \sf \:  =  \: \dfrac{cot\theta \: - 1 + cosec\theta \:}{cot\theta \: + 1  -  cosec\theta \:}

 \sf \:  =  \: \dfrac{(cosec\theta \: + cot\theta \:) - 1}{cot\theta \: + 1  -  cosec\theta \:}

 \sf \:  =  \: \dfrac{(cosec\theta \: + cot\theta \:) - ( {cosec}^{2}\theta \: -  {cot}^{2}\theta \:)  }{cot\theta \:  -  cosec\theta \: + 1}

 \sf \:  =  \: \dfrac{(cosec\theta \: + cot\theta \:) - (cosec\theta \: + cot\theta \:)(cosec\theta \: - cot\theta \:)}{cot\theta \: - cosec\theta \: + 1}

Take out cosecθ + cotθ common from numerator, we get

 \sf \:  =  \: \dfrac{(cosec\theta \: + cot\theta \:) \:  \cancel{(1 - cosec\theta \: + cot\theta \:)}}{ \cancel{cot\theta \: - cosec\theta \: + 1}}

 \sf \:  =  \: cosec\theta \: + cot\theta \:

 \bf \:  =  \: RHS

{\boxed{\boxed{\bf{Hence, Proved}}}}

Additional Information:-

Relationship between sides and T ratios

sin θ = Opposite Side/Hypotenuse

cos θ = Adjacent Side/Hypotenuse

tan θ = Opposite Side/Adjacent Side

sec θ = Hypotenuse/Adjacent Side

cosec θ = Hypotenuse/Opposite Side

cot θ = Adjacent Side/Opposite Side

Reciprocal Identities

cosec θ = 1/sin θ

sec θ = 1/cos θ

cot θ = 1/tan θ

sin θ = 1/cosec θ

cos θ = 1/sec θ

tan θ = 1/cot θ

Co-function Identities

sin (90°−x) = cos x

cos (90°−x) = sin x

tan (90°−x) = cot x

cot (90°−x) = tan x

sec (90°−x) = cosec x

cosec (90°−x) = sec x

Fundamental Trigonometric Identities

sin²θ + cos²θ = 1

sec²θ - tan²θ = 1

cosec²θ - cot²θ = 1

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