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प्रश्न
sec4A(1 - sin4A) - 2tan2A = 1
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उत्तर
डावी बाजू = sec4A(1 - sin4A) - 2tan2A
= sec4A[12 – (sin2A)2] – 2tan2A
= sec4A .(1 – sin2A) (1 + sin2A) – 2tan2A
= 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 – 2tan2A
= sec2A – tan2A
= 1 ................[∵ sec2θ – tan2θ = 1]
= उजवी बाजू
∴ sec4A(1 - sin4A) - 2tan2A = 1
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संबंधित प्रश्न
`tanA/(1 + tan^2A)^2 + cotA/(1 + cot^2A)^2` = sin A cos A
`tanθ/(secθ - 1) = (tanθ + secθ + 1)/(tanθ + secθ - 1)`
sec2θ + cosec2θ = sec2θ × cosec2θ
tan4θ + tan2θ = sec4θ - sec2θ
खालील प्रश्नासाठी उत्तराचा योग्य पर्याय निवडा.
sec2θ – tan2θ = ?
जर sec θ = `41/40`, तर sin θ, cot θ, cosec θ च्या किमती काढा.
`(tan(90 - theta) + cot(90 - theta))/("cosec" theta)` = sec θ हे सिद्ध करा.
`(sintheta + "cosec" theta)/sin theta` = 2 + cot2θ हे सिद्ध करा.
2(sin6A + cos6A) – 3(sin4A + cos4A) + 1 = 0 हे सिद्ध करा.
sin2θ + cos2θ ची किंमत काढा.
उकलः
Δ ABC मध्ये, ∠ABC = 90°, ∠C = θ°
AB2 + BC2 = `square` ...(पायथागोरसचे प्रमेय)
दोन्ही बाजूला AC2 ने भागून,
`"AB"^2/"AC"^2 + "BC"^2/"AC"^2 = "AC"^2/"AC"^2`
∴ `("AB"^2/"AC"^2) + ("BC"^2/"AC"^2) = 1`
परंतु `"AB"/"AC" = square "आणि" "BC"/"AC" = square`
∴ `sin^2 theta + cos^2 theta = square`
