Доказать тождество 1+sina=cosa+ctga/ctga

Question

Доказать тождество 1+sina=cosa+ctga/ctga

Answer 1

Cos(a)+ctg(a)/ctg(a) = (cos(a) + cos(a)/sin(a))/(cos(a)/sin(a)) = cos(a)*(1+1/sin(a))*sin(a)/cos(a) = 1+sin(a)