tg(180+b)=tgb=sinb/cosb cos(180-b)=-cosb tg(270+b)=-ctgb=-cosb/sinb
cos(270+b)=sinb tg(900-b)=(tg900+tgb)/(1-tg900tgb)=|tg900=tg(180+4п)=tg180=0|=tgb
tg(180+b)cos(180-b)/tg(270+b)cos(270+b)+tg(900-b)=
sinb
- -------cosb
cosb sinb
----------------------- =------------------
cosb cosb-tgb
- ---------sinb+tgb
sinb