Ответ Автор - natashanatasha8 (sin^2t-1+tg^2tcos^4t)/cos^4t=(sin^2t-1+cos^2tsin^2t)/cos^4t=(sin^2tcos^2t-cos^2t)/cos^4t==(sin^2t-1)/cos^2t=-cos^2t/cos^2t=-1