QQuestion
Prove the following identity:
(sin2 θ − 1)(tan2 θ + 1) + 1 = 0
Exam-ready answer • 04 Mark
✓Answer
Solving L.H.S. of the given equation :
⇒ (sin2 θ – 1)(tan2 θ + 1) + 1
⇒ (1 – cos2 θ – 1).sec2 θ + 1
⇒ -cos2 θ. sec2 θ + 1
\mathrm{LHS}=-\cos^2\theta\times\frac{1}{\cos^2\theta}+1LHS = −1 + 1
LHS = 0
Since LHS = RHS, (sin2 θ − 1)(tan2 θ + 1) + 1 = 0 is proved.
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