/* -*-ePiX-*- */
#include "epix.h"
using namespace ePiX;

int main()
{
  picture(P(0,-M_PI), P(M_PI,M_PI), "1.25 x 2.5in");
  offset(P(0,-0.5));

  begin();
  bold();
  double xa(M_PI_4), xb(2.25);
  P O(0,0);

  line(P(xmin(),0), P(xmax(),0));
  dashed();
  line(P(M_PI_2,ymin()), P(M_PI_2,ymax()));
  solid();

  line(P(xa,0), P(xa, Tan(xa)));
  line(P(xb,0), P(xb, Tan(xb)));

  set_crop();
  plot(Tan, xmin(), M_PI_2-0.001, 30);
  plot(Tan, M_PI_2+0.001, xmax(), 30);

  marker(P(xa, Tan(xa)), TIMES);
  marker(P(xb, Tan(xb)), TIMES);

  label(O, P(0,-2), "$O$", b);
  label(P(M_PI,0), P(0, 2), "$\\pi$", t);

  label(P(xa,0), P(0,-2), "$a$", b);
  label(P(xb,0), P(0, 2), "$b$", t);

  label(P(M_PI_2), P(-2,-2), "$\\frac{\\pi}{2}$", bl);

  label(P(M_PI_2, ymin()), P(0,-18), "\\textsc{Fig.~21}", b);

  tikz_format();

  end();
}