Mathc initiation/Fichiers h : x 18c01b


Sommaire



Installer et compiler ces fichiers dans votre répertoire de travail.

c01b.c
/* ---------------------------------- */
/* save as c01b.c                     */
/* ---------------------------------- */
#include "x_a.h"
/* ---------------------------------- */
# define   DEGREE     5
# define   COEFF_NB   DEGREE + 1
/* ---------------------------------- */
int main(void)
{
double x =  -5;
double remainder;

double *Pa  = I_Px( COEFF_NB);
double *Pt  = I_Px( COEFF_NB);
double *Pqr = I_Px( COEFF_NB);
double *Pq  = I_Px((COEFF_NB-1));

double a[COEFF_NB] = {3,0,-38,5,0,-1};

 clrscrn();
 
 c_a_Px(a,Pa);
 printf("\n If P(x) is : \n\n");
 p_Px(Pa);

 printf(" If we divide P(x) by : x - (%+.3f) \n\n",x);
 remainder = compute_horner(x,Pa,Pt,Pqr,Pq);
 p_horner(Pa,Pt,Pqr);

 printf(" The synthetic division indicates that the quotien is :\n\n");
 p_Px(Pq);

 printf(" The synthetic division indicates that P(%+.3f) = %+.3f\n\n",
        x, remainder);
        
 stop();
 
 free(Pa);
 free(Pt);
 free(Pqr);
 free(Pq);

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


Vérifier les calculs à la main. (Voir le premier exemple pour apprendre la méthode de Horner)


Exemple de sortie écran :

 
 If p_A is : 

   +3.00*x**5  -38.00*x**3  +5.00*x**2  -1.00  


 If we divide p_A by : x - (+3.000) 


     +3.00     +0.00    -38.00     +5.00     +0.00     -1.00   
     +0.00     +9.00    +27.00    -33.00    -84.00   -252.00   
   ------------------------------------------------------------
     +3.00     +9.00    -11.00    -28.00    -84.00   -253.00   


 The synthetic division indicates that the quotien is :

   +3.00*x**4  +9.00*x**3  -11.00*x**2  -28.00*x  -84.00  


 The synthetic division indicates that p_A(+3.000) = -253.000

 Press return to continue.


Fichier de commande gnuplot :
# ---------------------
# Copy and past this file into the screen of gnuplot
#
#
set zeroaxis lt 3 lw 1
plot [-1.:1.] [-10.:10.]\
    +3.00*x**5  -38.00*x**3  +5.00*x**2  -1.00
reset
# ---------------------