Tgxtg10°+tg10°tg50°+tg50°tgx=1
Tgxsin60/cos10cos50+sin10sin50/cos10cos50=1 √3/2tgx+1/2(cos40-cos60)=cos10cos50 √3/2tgx+1/2cos40-1/4=10cos40+1/4 √3/2tgx=1/2 tgx=√3/3 x=arctg√3/3+πk k∈Z