Question

выразите sina,cosa,tga и ctga через tga/2.

Answer 1

sina=(2tga/2)/(1+tg^2a/2)
cosa=(1-tg^2a/2)/(1+tg^2a/2)
tga=2tga/2/(1-tg^2a/2)
ctga=(1-tg^2a/2)/2tga/2