Question

100 баллов!!!!!!!!!!!!!!!!!​

Answer 1

$(tg\alpha -tg\beta)*Ctg(\alpha-\beta) -tg\alpha*tg\beta=\frac{Sin(\alpha-\beta)}{Cos\alpha Cos\beta} *\frac{Cos(\alpha-\beta)}{Sin(\alpha-\beta)}-\frac{Sin\alpha Sin\beta}{Cos\alpha Cos\beta} =\frac{Cos\alpha Cos\beta+Sin\alpha Sin\beta    }{Cos\alpha Cos\beta} -\frac{Sin\alpha Sin\beta}{Cos\alpha Cos\beta} =\frac{Cos\alpha Cos\beta+Sin\alpha Sin\beta-Sin\alpha Sin\beta}{Cos\alpha Cos\beta}=\frac{Cos\alpha Cos\beta}{Cos\alpha Cos\beta} =1$