Question

sec-tan/sec+tan=cos^2/(1+sin)^2

Answer 1

hope this helps...................

Answer 2

Here's your Answer

LHS

$\dfrac{sec - tan} {sec + tan}$

=> $\dfrac{1} {cos}$ - $\dfrac{sin} {cos}$ / $\dfrac{1} {cos}$ + $\dfrac{sin} {cos}$

=> $\dfrac{1-sin} {cos}$ / $\dfrac{1+sin} {cos}$

=> $\dfrac{1-sin} {1+sin}$

Squaring the term

=> $\dfrac{1-sin^2} {1+sin^2}$

=> $\dfrac{cos^2} {1+sin^2}$

Hence proved!!!

Hope it helps you :)