function [y1,y2,y3,y4,y5,y6,y7,y8] = quad_err(e)

y1 = (-2 + sqrt(4 - 4*e))/2; y2 = (-2 -sqrt(4 - 4*e))/2;
y3 = (-2 + sqrt(4 - 4*e))/2; y4 = e/y3;
y5 = (-2 -sqrt(4 - 4*e))/2; y6 = e/y5;

y7 = -4*e/(-2 -sqrt(4 - 4*e))/2; y8 = e/y7;