Question

(〖sin〗^4 θ-〖cos〗^4 θ)/(〖sin〗^2 θ-〖cos〗^2 θ)=1

Answer 1

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