How can I plot the functions in my code according to theta?

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Burak
Burak 2013-4-9
Here is my code.
clear all
format long
tic
N_cut=20;
eps0=(10^-9)/(36*pi);
mu0=4*pi*10^-7;
epsr1=1.;
epsr2=2.;
mur1=1.;
mur2=1.;
eps1=epsr1*eps0;
eps2=epsr2*eps0;
mu1=mur1*mu0;
mu2=mur2*mu0;
freq=299.7925*10^6;
omeg=2*pi*freq;
k=omeg*sqrt(eps1*mu1);
lambda=2*pi/k;
phi=45;
R=1.1;
for n=1:N_cut
bes_kur1(n)=sqrt(pi.*k.*R./2).*besselj(n+0.5,k.*R);
han_kur1(n)=sqrt(pi.*k.*R./2).*besselh(n+0.5,2,k.*R);
bes_kur_der1(n)=-n.*sqrt(pi.*k./(2.*R)).*besselj(n+0.5,k.*R)+k.*sqrt(pi.*k.*R./2).*besselj(n-0.5,k.*R);
han_kur_der1(n)=-n.*sqrt(pi.*k./(2.*R)).*besselh(n+0.5,2,k.*R)+k.*sqrt(pi.*k.*R/2).*besselh(n-0.5,2,k.*R);
han_kur_dd(n)=sqrt(pi.*k.*R./2).*besselh(n+2.5,2,k.*R)-sqrt(pi./(2.*k.*R)).*(2.*n+3).*besselh(n+1.5,2,k.*R)+sqrt(pi./(2.*(k.*R).^3)).*...
n.*(n+1).*besselh(n+0.5,2,k.*R);
a(n)=(1i.^(-n)).*(2.*n+1)./(n.*(n+1));
b(n)=(-a(n)).*bes_kur_der1(n)./han_kur_der1(n);
c(n)=(-a(n)).*bes_kur1(n)./han_kur1(n);
L1=legendre(n,cosd(theta));
L11=legendre(n-1,cosd(theta));
L2(n)=L1(2);
if n==1
L3(n)=0.;
else
L3(n)=L11(2);
end
L2_der(n)=(-(n+1).*L3(n)+n.*cosd(theta)).*L2(n)/sind(theta);
E_r=((-1i.*cosd(phi).*b(n).*L3(n).*(han_kur_dd(n)+han_kur1(n))));
E_theta=(cosd(phi)./(k.*R)).*((1i)*b(n)*han_kur_der1(n).*sin(theta).*L2_der(n)-c(n).*han_kur1(n)*(L3(n)./sin(theta)));
E_phi=(sin(phi))./(k.*R).*(((1i).*b(n).*han_kur_der1(n).*(L3(n)./(sin(theta))))-(c(n).*han_kur1(n).*sin(theta)).*L2_der(n));
end
F_Er=sum(E_r);
F_Etheta=sum(E_theta);
F_Ephi=sum(E_phi);
figure
plot(theta,abs(F_Er)),grid on
hold
figure
plot(theta,abs(F_Etheta)),grid on
hold
figure
plot(theta,abs(F_Ephi)),grid on
hold
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Burak
Burak 2013-4-9
yes exactly I want that , F_Er,F_Etheta , F_Ephi has to be function of theta.
Walter Roberson
Walter Roberson 2013-4-9
Hmmm, okay, but are you going to be doing anything with the formulas afterwards that you need them to be in function form? Or do you just need to be able to plot, in which case you could possibly proceed with numeric theta?

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Walter Roberson
Walter Roberson 2013-4-9
At the beginning of the code, put in
syms theta
then before you go to plot, you need to choose specific theta to plot for, such as by
Thetas = linspace(0, 2*pi, 100);
val_F_Er = double( subs(F_er, theta, Thetas) );
val_F_Etheta = double( subs(F_Etheta, theta, Thetas) );
val_F_Ephi = double( subs(F_Ephi, theta, Thetas) );
figure
plot(Thetas, abs(val_F_Er));
figure
plot(Thetas, abs(val_F_Etheta));
figure
plot(Thetas, abs(val_F_Ephi));
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