Question

Помогите,на завтра,срочно 2-cos²L-sin²L= -sin²L-cos²L=

Answer 1

$2-cos^2L-sin^2L=2-(cos^2L+sin^2L)=2-1=1\\ -sin^2L-cos^2L=-cos^2L-sin^2L=-(cos^2L+sin^2L)=-1\\ \frac{cos^2L-1}{sin^2L-1} = \frac{cos^2L-(sin^2L+cos^2L)}{sin^2L-(cos^2L-sin^2L)} = \frac{-sin^2L}{-cos^2L} =tg^2L$