(sina-cosa)^2-1\ctg-sina*cos-2tg^2a

1)(sina-cosa)²-1=sin²a-2sinacosa+cos²a-sin²a-cos²a=-2sinacosa 2)ctga-sina*cosa=cosa/sina -sinacosa=(cosa-sin²acosa)/sina= =cosa(1-sin²a)/sina=cos³a/sina 3)-2sinacosa*sina/cos³a=-2sin²a/cos²a=-2tg²a 4)-2tg²a-2tg²a=-4tg²a