/* ------------------------------------ */
/*  Save as :   c01.c                   */
/* ------------------------------------ */
#include "x_ahfile.h"
#include       "fa.h"
/* ------------------------------------ */
int main(void)
{
double n = 0;

   printf(" Draw the normal vector at the point P.\n\n"
          " f : (x,y)-> %s\n\n", feq);

 while((n+=.05)<2.8)

     G_3d_v(i_WsGnuplot(-3,3,-3,3,-.5,2),
            i_VGnuplot( 94.,22.,1.,1.),
            feq,f,f_z,
            i_point2d(n,0.));

printf(" Open the file \"a_main.plt\" with Gnuplot.\n\n"
       " Use the \"replot\" command of gnuplot.    \n\n"
       " Press return to continue.                 \n\n");

 getchar();

 return 0;
}