SA3 marksYear: 2023MediumCBSE Class 10
trigonometryidentitiesproof
Question
Prove that: (cosθ1−cosθ)(sinθ1−sinθ)=tanθ+cotθ1
Solution
1
LHS =cosθ1−cos2θ×sinθ1−sin2θ
+0.5 marks2
=cosθsin2θ×sinθcos2θ=sinθcosθ
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RHS =tanθ+cotθ1=cosθsinθ+sinθcosθ1
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=cosθsinθsin2θ+cos2θ1=sinθcosθ. ∴ LHS = RHS
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