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If sin x + cos x = √3 cos x, then the value of cot x is:1. \(\frac{{\sqrt 3 + 1}}{2}\)2. √33. 14. \(\frac{{\sqrt 3 -1}}{2}\) |
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Answer» Correct Answer - Option 1 : \(\frac{{\sqrt 3 + 1}}{2}\) Given: sin x + cos x = √3 cos x Concept used: Rationalization method used. Formula used: Tanθ = Sinθ/Cosθ a2 – b2 = (a + b) × (a – b) Calculation: sin x + cos x = √3 cos x ⇒ (sin x + cos x)/cos x = √3 ⇒ (sin x/cos x + cos x/cos x ) = √3 ⇒ tan x + 1 = √3 ⇒ tan x = √3 – 1 ⇒ 1/cot x = √3 – 1 ⇒ cot x = 1/(√3 – 1) ⇒ cot x = (√3 + 1)/[(√3 – 1) × (√3 + 1)] ⇒ cot x = (√3 + 1)/[(√3)2 – 1] ⇒ cot x = (√3 + 1)/(3 – 1) ⇒ cot x = (√3 + 1)/2 ∴ The value of cot x is (√3 + 1)/2. |
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