Mathc initiation/Fichiers c : c23ca

Sommaire

Installer et compiler ces fichiers dans votre répertoire de travail.

	c3a.c

/* --------------------------------- */
/* save as c3a.c                     */
/* --------------------------------- */
#include "x_hfile.h"
#include      "fa.h"
/* --------------------------------- */
int main(void)
{
double c  = 1;

 clrscrn();
 printf("  f : x-> %s\n\n" 
        " Df : x-> %s\n\n\n", feq, Dfeq);

 printf("  Compute the derivative of f when x = %0.3f\n\n", c);   
  
 printf("  with   Df(%0.3f) = %0.8f    \n",c, Df(c));
 printf("  with fx_x(%0.3f) = %0.8f\n\n\n",c, fx_x(f,c,H));
 stop();
 
 clrscrn();
 printf("  The equation of the tangente \n\n"); 
 eq_Tan(c, f, Df);
 
 printf("  The equation of the tangente (with the function : fx_x();)\n\n"); 
 eq_tan(c, f);  
 stop();
 
 clrscrn();
 printf("  The equation of the normal \n\n"); 
 eq_Norm(c, f, Df);
 
 printf("  The equation of the normal (with the function : fx_x();)\n\n"); 
 eq_norm(c, f); 
 
 stop();


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

Dessinons la tangente et la normale, pour vérifier la qualité de notre fonction fx_x();.

set size ratio -1

La commande ci-dessus est importante pour que la normale soit bien perpendiculaire à la tangente.

Fichier de commande gnuplot :

# ---------------------
# Copy and past this file into the screen of gnuplot
#
# 
set size ratio -1
set zeroaxis lt 3 lw 1
set grid
plot [ -4.:4.] [-7.:1.]\
  3.0*x**2 - 2.0*x - 5.0,\
          4.000*x -8.000,\
         -0.250*x -3.750
reset
# ---------------------

Exemple de sortie écran :

  f : x-> 3.0*x**2 - 2.0*x - 5.0

 Df : x-> 6.0*x - 2.0


  Compute the derivative of f when x = 1.000

  with   Df(1.000) = 4.00000000    
  with fx_x(1.000) = 4.00000000


 Press return to continue. 


**********************


  The equation of the tangente 

 4.000*x -8.000


  The equation of the tangente (with the function : fx_x();)

 4.000*x -8.000


 Press return to continue. 


**********************


  The equation of the normal 

 -0.250*x -3.750


  The equation of the normal (with the function : fx_x();)

 -0.250*x -3.750


 Press return to continue.