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Sec4A(1 - sin4A) - 2tan2A = 1 - Mathematics 2 - Geometry [गणित २ - भूमिती]

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Question

sec4A(1 - sin4A) - 2tan2A = 1 

Sum

Solution

डावी बाजू = sec4A(1 - sin4A) - 2tan2A

= sec4A[12 – (sin2A)2] – 2tan2A  

= sec4A .(1 – sin2A) (1 + sin2A) – 2tan2

= sec4A cos2A (1 + sin2A) – 2tan2A ...`[(∵ sin^2θ + cos^2θ = 1), (∴ 1 - sin^2θ = cos^2θ)]` 

= `1/cos^4A . cos^2A(1 + sin^2A) - 2tan^2A`

= `1/cos^2A (1 + sin^2A) - 2tan^2A`

= `1/cos^2A + sin^2A/cos^2A - 2tan^2A`

= sec2A + tan2A – 2tan2

= sec2A – tan2

= 1 ................[∵ sec2θ – tan2θ = 1] 

= उजवी बाजू

∴ sec4A(1 - sin4A) - 2tan2A = 1  

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त्रिकोणमितीय नित्यसमानता
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Chapter 6: त्रिकोणमिती - सरावसंच 6.1 [Page 132]

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Balbharati Geometry (Mathematics 2) [Marathi] 10 Standard SSC Maharashtra State Board
Chapter 6 त्रिकोणमिती
सरावसंच 6.1 | Q 6. (11) | Page 132
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