Question

Протяните руку помощи..

Answer 1

sin(a+b)/2=cosc/2
a+b+c=180°
(a+b)/2=180°/2)-c/2=90°-c/2
sin(a+b)/2=sin(90°-c/2)=cosc/2


tg(a+b)/2=tg(90°-c/2)=
ctgc/2