SA3 marksYear: 2025MediumCBSE Class 10
trigonometrytrigonometric-identitiesproof
Question
Prove that: (1+tan2θ1)(1+cot2θ1)=sin2θ−sin4θ1
Solution
1
LHS =(1+cot2θ)(1+tan2θ)=csc2θ⋅sec2θ
+1 mark2
=sin2θ1⋅cos2θ1=sin2θ⋅cos2θ1
+1 mark3
=sin2θ(1−sin2θ)1=sin2θ−sin4θ1 = RHS
+1 mark