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प्रश्न
`tanA/(1 + tan^2A)^2 + cotA/(1 + cot^2A)^2` = sin A cos A
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उत्तर
डावी बाजू = `tanA/(1 + tan^2A)^2 + cotA/(1 + cot^2A)^2`
= `tanA/(sec^2A)^2 + cotA/(cosec^2A)^2` .........`[(∵ 1 + tan^2θ = sec^2θ), (∴ 1 + cot^2θ = cosec^2θ)]`
= `tanA/sec^4A + cotA/(cosec^4A)`
= `tanA xx 1/sec^4A + cotA xx 1/(cosec^4A)`
= `sinA/cosA xx cos^4A + cosA/sinA xx sin^4A`
= sin A cos3A + cos A sin3A
= sin A cos A(cos2A + sin2A)
= sin A cos A (1) ........[∵ sin2θ + cos2θ = 1]
= sin A cos A
= उजवी बाजू
∴ `tanA/(1 + tan^2A)^2 + cotA/(1 + cot^2A)^2` = sin A cos A
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संबंधित प्रश्न
`(sin^2θ)/(cosθ) + cosθ = secθ`
`tanθ/(secθ - 1) = (tanθ + secθ + 1)/(tanθ + secθ - 1)`
`1/(1 - sinθ) + 1/(1 + sinθ)` = 2sec2θ
जर tan θ + cot θ = 2, तर tan2θ + cot2θ = ?
sec2θ + cosec2θ = sec2θ × cosec2θ हे सिद्ध करा.
जर 3 sin θ = 4 cos θ, तर sec θ = ?
`"tan A"/"cot A" = (sec^2"A")/("cosec"^2"A")` हे सिद्ध करा.
जर sec θ = `41/40`, तर sin θ, cot θ, cosec θ च्या किमती काढा.
`(1 + sintheta)/(1 - sin theta)` = (sec θ + tan θ)2 हे सिद्ध करा.
जर sin θ + cos θ = `sqrt(3)`, तर tan θ + cot θ = 1 हे दाखवा.
