Math Help - Trig

1. Trig

please check my attach and prove it!. It is ms word document.7uy7.doc

2. Re: Trig

$\frac{1}{sec^2x-cos^2x}$
$=\frac{cos^2x}{1-cos^4x}$
$=\frac{cos^2x}{(1-cos^2x)(1+cos^2x)}$
$=\frac{cos^2x}{sin^2x(1+cos^2x)}$

Do similar thing for the other term and simplify.