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If sin θ + cos θ = 3, then show that tan θ + cot θ = 1 - Geometry Mathematics 2

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प्रश्न

If sin θ + cos θ = `sqrt(3)`, then show that tan θ + cot θ = 1

योग
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उत्तर

sin θ + cos θ = `sqrt(3)`     ......[Given]

∴ (sin θ + cos θ)2 = 3    ......[Squaring on both sides]

∴ sin2θ + 2sinθ cosθ + cos2θ = 3  ......[∵ (a + b)2 = a2 + 2ab + b2]

∴ (sin2θ + cos2θ) + 2sinθ cosθ = 3

∴ 1 + 2 sin θ cos θ = 3   ......[∵ sin2θ + cos2θ = 1]

∴ 2 sin θ cos θ = 2

∴ sin θ cos θ = 1   ......(i)

tan θ + cot θ = `sintheta/costheta + costheta/sintheta`

= `(sin^2theta + cos^2theta)/(costhetasintheta)`

= `1/(sintheta costheta)`   ......[∵ sin2θ + cos2θ = 1]

= `1/1`    ......[From (i)]

= 1

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