Question

Prove that ${\sec }^{2}A-{\tan }^{2}A=1$

Answer 1

$\frac{1}{co{s}^{2}A}-\frac{si{n}^{2}A}{co{s}^{2}A}$

or, $\frac{co{s}^{2}A}{co{s}^{2}A}=1$

Hence $L.H.S=R.H.S$