Mathc initiation/Fichiers h : x 18c02a


Sommaire



Installer et compiler ces fichiers dans votre répertoire de travail.

c02a.c
/* ---------------------------------- */
/* save as c02a.c                     */
/* ---------------------------------- */
#include "x_a.h"
/* ---------------------------------- */
# define   DEGREE     3
# define   COEFF_NB   DEGREE + 1
/* ---------------------------------- */
int main(void)
{
double x = -11;
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]={1,8,-29,44};

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

 printf(" Verify if %+.3f is a root of P(x) \n\n",x);
 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 P(%+.3f) = %+.3f\n\n",
        x, remainder);
 printf(" So %+.3f is a root of P(x) \n\n",x);

 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 : 

   + x**3  +8.00*x**2  -29.00*x  +44.00  


 Verify if -11.000 is a root of p_A   



 If we divide p_A by : x - (-11.000)


     +1.00     +8.00    -29.00    +44.00   
     +0.00    -11.00    +33.00    -44.00   
   ----------------------------------------
     +1.00     -3.00     +4.00     +0.00   


 The synthetic division indicates that p_A(-11.000) = +0.000

 So -11.000 is a root of p_A 

 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 [-12.:7.] [-5.:400.]\
      + x**3  +8.00*x**2  -29.00*x  +44.00
reset
# ---------------------


Fichier de commande gnuplot :
# ---------------------
# Copy and past this file into the screen of gnuplot
#
#
set zeroaxis lt 3 lw 1
plot [-12.:-10] [0.:20.]\
      + x**3  +8.00*x**2  -29.00*x  +44.00
reset
# ---------------------