SA3 marksYear: 2020MediumCBSE Class 10
trigonometryidentitiesproof
Question
If sinθ+cosθ=2, prove that tanθ+cotθ=2. Solution
1
sinθ+cosθ=2. Squaring both sides: sin2θ+cos2θ+2sinθcosθ=2 +1 mark2
1+2sinθcosθ=2⇒sinθcosθ=21. So tanθ+cotθ=cosθsinθ+sinθcosθ
+1 mark3
=sinθcosθsin2θ+cos2θ=211=2. Hence tanθ+cotθ=2
+1 mark