# how to plot equation containing bessel functions

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philippe on 8 Apr 2013
Hello, I am struggling on this equation since some days. because I followed the theoretical equation of plate response but the plot still not correct. Please could you have a look on my script.
clc clear
%propriétés de la plaque
% épaisseur
h=0.001;
% fréquence
f = 100; %Hz
% nombre d'onde
k = 1000;
%%%%%%%%%%%%%
v0 =4 ;
n = 1000;
w = 2*pi*f;
% vecteur position
% longueur
lx=10;
% nb d'échantillons
Nx=512;
dx=lx/Nx;
rx=dx:dx:lx-dx;
% champ vx
J0 = besselj(0,k*rx); %fonction de bessel d ordre 0
J0i = besselj(0,1i*k*rx);
N0 = besseli(0,k*rx); %fonction de bessel d ordre 0 modifiée
N0i= besseli(0,1i*k*rx);
t1=0;
t2=0.023;
t3=2*t2;
v1t= v0*(J0+1i*N0-1i*J0i-1i*N0i)*exp(-1i*2*pi*f*t1);
v2t= v0*(J0+1i*N0-1i*J0i-1i*N0i)*exp(-1i*2*pi*f*t2);
v3t= v0*(J0+1i*N0-1i*J0i-1i*N0i)*exp(-1i*2*pi*f*t3);
figure(1)
plot(rx,real(v1t),'r',rx,real(v2t),'b',rx,real(v3t),'g',rx,real(v3t)*0,'k');
break;

Youssef Khmou on 8 Apr 2013
hi,
change lx to :
lx=0.7;
fine?

#### 1 Comment

philippe on 9 Apr 2013
hi, no it is just the factor of the samples number.

philippe on 9 Apr 2013
hi,
But the problem is that the three functions shouldn't cross in zero at the same time because they are shifted between the three times. this is how the plot should be.
Thanks

philippe on 10 Apr 2013
any one has tried it before ?