What is the simplified value of (sec A + cos A)(sec A - cos A)?
Expression : $$(secA+cosA)(secA-cosA)$$
= $$(\frac{1}{cosA}+cosA)(\frac{1}{cosA}-cosA)$$
= $$(\frac{1+cos^2A}{cosA})(\frac{1-cos^2A}{cosA})$$
= $$(1+cos^2A)(\frac{sin^2A}{cos^2A})$$
= $$\frac{sin^2A}{cos^2A}+sin^2A$$
= $$tan^2A+sin^2A$$
=> Ans - (D)
Create a FREE account and get:
