Question

cos 2 альфа - sin^2 альфа / 2sin^2 альфа -cos^2 альфа

Answer 1

(cos(2a)-(sin(a))^2)/(2(sin(a))^2-(cos(a))^2)=
=((cos(a)^2-(sin(a))^2-(sin(a))^2)/(2(sin(a))^2-(cos(a))^2)=
-((2(sin(a))^2-(cos(a))^2)/(2(sin(a))^2-(cos(a))^2)=-1

формула cos(2a)=(cos(a))^2-(sin(a))^2