Question

Prove that
$\frac{\sec \theta -1}{\sec \theta +1}=\frac{1-\cos \theta }{1+\cos \theta }$

Answer 1

Solving LHS,

$\frac{\sec \theta -1}{\sec \theta +1}$

$⟹\frac{\frac{1}{\cos \theta }-1}{\frac{1}{\cos \theta }+1}$

$⟹\frac{1-\cos \theta }{1+\cos \theta }$ = RHS

Hence proved.