Question

Verifique a identidade​

Answer 1

$\frac{cossec^2x-2}{cossec^2x} =\frac{\frac{1}{sen^2x} -2}{\frac{1}{sen^2x} } \\\\\frac{\frac{1}{sen^2x} }{\frac{1}{sen^2x} } -\frac{2}{\frac{1}{sen^2x} } =\frac{sen^2x}{sen^2x} -2sen^2x=1-2sen^2x=cos^2x-sen^2x$