graph1(uncomp)

import geometry;
import graph;
import contour;

size(9cm, 0);
defaultpen(fontsize(12pt));
dotfactor = 4;
picture axis;

real xmin = -5, xmax = 5,
     ymin = -5, ymax = 5;
xaxis(axis, xmin=xmin, xmax=xmax,
    Ticks(scale(.7)*Label(align=E, Fill(white) ),
          NoZero,
          beginlabel=false, endlabel=false,
          begin=false, end=false,
          Step=0, step=0,
          Size=0mm, size = 0mm),
          Arrow(2mm),true);

yaxis(axis, ymin=ymin, ymax=ymax,
    // Ticks(scale(.7)*Label(align=W, Fill(white) ),
    //      NoZero,
    //      beginlabel=false, endlabel=false,
    //      begin=false, end=false,
    //      Step=0, step=0,
    //      Size=0mm, size = 0mm),
          Arrow(2mm),true);

real f(real x){return (x^2-3*x-1)/(x^2+1);}
//guide[][] Cf = contour(f,(xmin,ymin),(xmax,ymax),nx=400,ny=400, new real[]{0}, operator ..);
path Cf = graph(f, xmin, xmax, n = 400);
line x = line((xmin,0),(xmax,0));
point[] fp = intersectionpoints( x, Cf);
path Df=buildcycle(Cf, (xmax,0)--(xmin,0));

fill(Df,green);
draw(Cf, green+1pt);

label("$x$", (xmax,0), 2S);
label("$y$", (0,ymax), 2W);
label("$a$", fp[0],SW );
label("$b$", fp[1],SE );
dot(fp[0]^^fp[1]);
//label(scale(.7)*"$0$", origin, S+W, UnFill);
ylimits(ymin, ymax, Crop);
add(axis);
addMargins(2mm,2mm);