23/07/15 06:45:14.76 X1xEkNEDH.net
nine_point_circle <- \(x1,y1,x2,y2,x3,y3){
x9 = ((x1/2+x2/2)^2*(-(y2/2+y3/2)) + (x1/2+x2/2)^2*(y3/2+y1/2) - (y1/2+y2/2)^2*(y2/2+y3/2) + (y1/2+y2/2)^2*(y3/2+y1/2) + (y1/2+y2/2)*(x2/2+x3/2)^2 + (y1/2+y2/2)*(y2/2+y3/2)^2 - (y1/2+y2/2)*(x3/2+x1/2)^2 - (y1/2+y2/2)*(y3/2+y1/2)^2 - (x2/2+x3/2)^2*(y3/2+y1/2) - (y2/2+y3/2)^2*(y3/2+y1/2) + (y2/2+y3/2)*(x3/2+x1/2)^2 + (y2/2+y3/2)*(y3/2+y1/2)^2)/(2*(-(x1/2+x2/2)*(y2/2+y3/2) + (x1/2+x2/2)*(y3/2+y1/2) + (y1/2+y2/2)*(x2/2+x3/2) - (y1/2+y2/2)*(x3/2+x1/2) - (x2/2+x3/2)*(y3/2+y1/2) + (y2/2+y3/2)*(x3/2+x1/2)))
y9 = -((x1/2+x2/2)^2*(-(x2/2+x3/2)) + (x1/2+x2/2)^2*(x3/2+x1/2) + (x1/2+x2/2)*(x2/2+x3/2)^2 + (x1/2+x2/2)*(y2/2+y3/2)^2 - (x1/2+x2/2)*(x3/2+x1/2)^2 - (x1/2+x2/2)*(y3/2+y1/2)^2 - (y1/2+y2/2)^2*(x2/2+x3/2) + (y1/2+y2/2)^2*(x3/2+x1/2) - (x2/2+x3/2)^2*(x3/2+x1/2) + (x2/2+x3/2)*(x3/2+x1/2)^2 + (x2/2+x3/2)*(y3/2+y1/2)^2 - (y2/2+y3/2)^2*(x3/2+x1/2))/(2*(-(x1/2+x2/2)*(y2/2+y3/2) + (x1/2+x2/2)*(y3/2+y1/2) + (y1/2+y2/2)*(x2/2+x3/2) - (y1/2+y2/2)*(x3/2+x1/2) - (x2/2+x3/2)*(y3/2+y1/2) + (y2/2+y3/2)*(x3/2+x1/2)))
Ce=x9+1i*y9
r=abs((x1/2+x2/2)+1i*(y1/2+y2/2)-Ce)
list(Center=c(x9,y9),Radius=Re(r))
}