Mathc initiation/Fichiers h : c42fb

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	`c00b.c`

/* --------------------------------- */
/* save as  c00b.c                   */
/* --------------------------------- */
#include  "x_hfile.h"
#include       "fb.h"
/* --------------------------------- */
int main(void)
{
CTRL_splot w;

w.xmin = -4.0; w.xmax = +4.00;
w.ymin = -2.0; w.ymax = +2.00;

double     x = 0.0;  /* x = (PI/2)-.2; */
double cstep = 0.1;

   circle(1./K_y_2d(f,x),
          h_y_2d(f,x),
          k_y_2d(f,x),
          cstep);

   G_C_2d(w,
          f,x,
          feq
          );

 clrscrn();
 
 printf(" If a smooth curve C is the graph"
        " of y = %s \n"
        " then the curvature K at P(x,y) is\n\n\n"
        " K = |y''| / [1 + y'^2]^(3/2)     \n\n\n"

        " If P(x,y) is a point on the graph"
        " of y = f(x)  \n"
        " at which K != 0. The point M(h,k)"
        " is the center\n"
        " of the cuvature for P if   \n\n\n"
        " h = x - y'[1 + y'^2] / y''     \n"
        " k = y +   [1 + y'^2] / y'' \n\n\n"

        " The radius is r = 1/K \n\n\n"

        " ... load \"a_main.plt\" ... with gnuplot.  \n\n",feq);

 stop();

 return 0;
}
/* --------------------------------- */
/* --------------------------------- */

Exemple de sortie écran :

 If a smooth curve C is the graph of y = cos(x) 
 then the curvature K at P(x,y) is


 K = |y''| / [1 + y'^2]^(3/2)     


 If P(x,y) is a point on the graph of y = f(x)  
 at which K != 0. The point M(h,k) is the center
 of the cuvature for P if   


 h = x - y'[1 + y'^2] / y''     
 k = y +   [1 + y'^2] / y'' 


 The radius is r = 1/K 


 Open the file "a_main.plt" with Gnuplot.

 Press return to continue.