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प्रश्न
Prove that `"cosec" θ xx sqrt(1 - cos^2theta)` = 1
उत्तर
L.H.S = `"cosec" θ xx sqrt(1 - cos^2theta)`
= `"cosec" θ xx sqrt(sin^2theta)` ......`[(because sin^2theta + cos^2theta = 1),(therefore 1 - cos^2theta = sin^2theta)]`
= cosec θ × sin θ
= 1 ......[∵ sin θ × cosec θ = 1]
= R.H.S
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Solution :
L.H.S. = cotθ + tanθ
= `cosθ/sinθ + sinθ/cosθ`
= `(square + square)/(sinθ xx cosθ)`
= `1/(sinθ xx cosθ)` ............... `square`
= `1/sinθ xx 1/square`
= cosecθ × secθ
L.H.S. = R.H.S
∴ cotθ + tanθ = cosecθ × secθ
