Question

1-costheta/1+costheta = (cosec theta - cottheta)2

Answer 1

See the attachement But reverse it to get answer

Answer 2

$\frac{1 - cos \theta}{1 + cos \theta} \\ \\ = \frac{( {1 - cos \theta)}^{2} }{1 - {cos}^{2} \theta } \\ \\ = \frac{ {(1 - cos \theta)}^{2} }{ {sin}^{2} \theta} \\ \\ = ( { \frac{1 - cos \theta}{sin \theta} })^{2} \\ \\ = ( {cosec \theta - cot \theta)}^{2}$