Упростите выражения: cos(α-β)(tgαtgβ-1)+(1+tgαtgβ)cos(α+β) Решения нужно

Ответ. cos(α-β)*(tg(α)*tg(β)-1)+(1+tg(α)*tg(β))*cos(α+β)= cos(α-β)*((sin(α)*sin(β)-cos(α)*cos(β))/(cos(α)*cos(β))+((cos(α)*cos(β)+sin(α)*sin(β))/(cos(α)*cos(β))*cos(α+β)=(-cos(α-β)*cos(α+β))/(cos(α)*cos(β))+(cos(α+β)*cos(α-β))/(cos(α)*cos(β))=(cos(α+β)*cos(α-β)-cos(α-β)*cos(α+β))/(cos(α)*cos(β))=0[