Mathc initiation/a616
Installer et compiler ces fichiers dans votre répertoire de travail.
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c1fsN.c |
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/* ---------------------------------- */
/* save as c1fsN.c */
/* ---------------------------------- */
#include "x_hfile.h"
/* ---------------------------------- */
#define N 50
/* ---------------------------------- */
#include "f1.h"
/* ---------------------------------- */
int main(void)
{
double T = 2.;
double omega = (2.*PI/T);
double a = -1;
double b = +1;
double A[N+1];
double B[N+1];
int n = 0;
A[0] = 1./T * fourier_a0(f, a,b);
for( n=1; n<=N; n++)
{
A[n] = 2./T * fourier_an(f, a,b, omega, n);
B[n] = 2./T * fourier_bn(f, a,b, omega, n);
}
clrscrn();
printf(" S(x) = %.9f\\\n", A[0]);
for( n=1; n<N; n++)
printf(" %+.9f*cos(%.9f* %d*x) %+.9f*sin(%.9f* %d*x)\\\n",
A[n], omega, n,
B[n], omega, n);
printf(" %+.9f*cos(%.9f* %d*x) %+.9f*sin(%.9f* %d*x)\n",
A[n], omega, n,
B[n], omega, n);
stop();
return 0;
}
/* ---------------------------------- */
/* ---------------------------------- */
Exemple de sortie écran :
0.333333333\
-0.405284728*cos(3.141592654* 1*x) +0.636619776*sin(3.141592654* 1*x)\
+0.101321157*cos(3.141592654* 2*x) -0.318309914*sin(3.141592654* 2*x)\
-0.045031578*cos(3.141592654* 3*x) +0.212206684*sin(3.141592654* 3*x)\
...
+0.000150672*cos(3.141592654* 48*x) -0.013779127*sin(3.141592654* 48*x)\
-0.000141849*cos(3.141592654* 49*x) +0.013549424*sin(3.141592654* 49*x)\
+0.000133333*cos(3.141592654* 50*x) -0.013333333*sin(3.141592654* 50*x)
Fichier de commande gnuplot :
# ---------------------
# Copy and past this file into the screen of gnuplot
#
#
plot [-1:1] [-.5:2.]\
(x*(x+1)),\
+0.333333333\
-0.405284728*cos(3.141592654* 1*x) +0.636619776*sin(3.141592654* 1*x)\
+0.101321157*cos(3.141592654* 2*x) -0.318309914*sin(3.141592654* 2*x)\
-0.045031578*cos(3.141592654* 3*x) +0.212206684*sin(3.141592654* 3*x)\
+0.025330190*cos(3.141592654* 4*x) -0.159155164*sin(3.141592654* 4*x)\
-0.016211224*cos(3.141592654* 5*x) +0.127324386*sin(3.141592654* 5*x)\
+0.011257671*cos(3.141592654* 6*x) -0.106104043*sin(3.141592654* 6*x)\
-0.008270792*cos(3.141592654* 7*x) +0.090946870*sin(3.141592654* 7*x)\
+0.006332148*cos(3.141592654* 8*x) -0.079579249*sin(3.141592654* 8*x)
reset