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Question
जर 1 – cos2θ = `1/4`, तर θ = ?
Solution
1 – cos2θ = `1/4` ......[दिलेले]
∴ sin2θ = `1/4` .....`[(because sin^2theta + cos^2theta = 1),(therefore 1 - cos^2theta = sin^2theta)]`
∴ sin θ = `1/2` ......[दोन्ही बाजूंचे वर्गमूळ घेऊन]
∴ θ = 30° ......`[because sin 30^circ = 1/2]`
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RELATED QUESTIONS
`sqrt((1 - sinθ)/(1 + sinθ))` = secθ - tanθ
(sec θ - cos θ)(cot θ + tan θ) = tan θ sec θ
secθ + tanθ = `cosθ/(1 - sinθ)`
`tanθ/(secθ - 1) = (tanθ + secθ + 1)/(tanθ + secθ - 1)`
sec θ(1 - sin θ) (sec θ + tan θ) = 1
`(sin θ - cos θ + 1)/(sin θ + cos θ - 1) = 1/(sec θ - tan θ)`
खालील प्रश्नासाठी उत्तराचा योग्य पर्याय निवडा.
sin2θ + sin2(90 – θ) = ?
जर cos A + cos2A = 1, तर sin2A + sin4A = ?
जर tan θ – sin2θ = cos2θ, तर sin2θ = `1/2` हे दाखवा.
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`
