/* -*-ePiX-*- */
#include "epix.h"
using namespace ePiX;
/*
P midpt(const P& tail, const P& head)
{
  return 0.5*(tail + head);
}
*/
P f(double t)
{
  return P(t, t*t);
}

int main()
{
  picture(P(-1.75, 0), P(1.75, 3), "2.1 x 1.8in");

  begin();
  bold();
  P pO(0,0), pP0(f(0.625)), pP1(f(1.5)), pN(pP1.x1(), pP0.x2());

  line(P(-2, 0), P(2, 0));
  line(pO, P(0,ymax()));

  plot(f, xmin(), xmax(), 40);

  line(pP1&E_1, pP1);
  line(pP0, pN);
  line(pP0, pP1);

  dot(f(-1), P(2, 2), "$(-1, 1)$", r);
  dot(f( 1), P(0,-2), "$(1, 1)$",  br);
  label(pO, P(0,-4), "$(0, 0)$", b);

  label(pP0, P(-2,4), "$P_{0}$", l);
  label(pP1, P(-2,2), "$P_{1}$", l);
  label(pN,  P( 2,0), "$N$", r);

  label(pP1, P( 4,0), "$y = x^{2}$", r);

  tikz_format();
  end();
}