Ответы и объяснения

  • Участник Знаний
2014-01-11T03:56:28+00:00
Cos²a-cos²a/sin²a+1=(sin²acos²a-cos²a+sin²a)/sin²a=(1/4sin²2a-cos2a)/sin²a=
(sin²2a-4cos2a)/4sin²a
(sin²acos²a+sin²a-1)/cos²a=(1/4sin²2a-cos²a)/cos²a=(sin²2a-4cos²a)/4cos²a

(sin²2a-4cos2a)/4sin²a:(sin²2a-4cos²a)/4cos²a=(sin²2a-4cos2a)/4sin²a:*4cos²a/(sin²2a-4cos²a)=ctg²a
ctg²a=ctg²a