clear; close all; es = [0 0.2 0.5 0.8 0.999]; a = 1; L = 2*a; for idx=1:length(es) e = es(idx); D = L*e; c = D/2; b = sqrt(a^2-c^2); theta = linspace(0,2*pi,50); x = a*cos(theta)-c; y = b*sin(theta); plot(x,y,'DisplayName',sprintf('e=%.3g',e)); hold on; axis equal; end legend(); plot(0,0,'bx','HandleVisibility','off'); text(0,0.1,'F'); big;