Ответы и объяснения

2013-04-23T14:44:27+00:00

(cos^2-ctg^2)/(tg^2-sin^2)=(cos^2-cos^2/sin^2)/(sin^2/cos^2-sin^2)=((cos^2*sin^2-cos^2)/sin^2)/((sin^2-sin^2*cos^2)/cos^2)=((cos^2/sin^2)*(sin^2-1))/((sin^2/cos^2)*(1-cos^2))=((cos^2/sin^2)*(-cos^2))/((sin^2/cos^2)*sin^2)=cos^6/sin^6=ctg^6