I am trying to a series generated from complex function but it gives to me an error.

clear;
clc;
syms k
Delta=0;
chi=0;
theta=0;
alpha=5;
phi=0;

bn=exp(-0.5*alpha^2)*(alpha^k)/sqrt(gamma(k+1));
bn1=exp(-0.5*alpha^2)*(alpha^(k+1))/sqrt(gamma(k+2));

t = 0:pi/100:2*pi;
Gamma=chi*k^2-0.5*Delta;
Wn=0.5*Delta-chi*k;
mu=sqrt((0.5*Delta-chi*k)+k+1);
An=exp(-1i*Gamma*t)*(bn*cos(theta/2)*(cos(mu*t)-1i*Wn*sin(mu*t)/mu)-1i*bn1*sqrt(k+1)*sin(theta/2)*exp(-1i*phi)*sin(mu*t)/mu);

zz=real(An)^2+2*imag(An);
y1 = symsum(zz,k, 0, 20);
plot(t,y1,'r','Color',[0.5 0 0.8])

Error using mupadmex

Error in MuPAD command: The dimensions do not match. [(Dom::Matrix(Dom::ExpressionField()))::_mult2]

Error in sym/privBinaryOp (line 820)

Csym = mupadmex(op,args{1}.s, args{2}.s, varargin{:});

Error in * (line 216)

X = privBinaryOp(A, B, 'symobj::mtimes');

Error in Untitled222 (line 17)

An=exp(-1i*Gamma*t)*(bn*cos(theta/2)*(cos(mu*t)-1i*Wn*sin(mu*t)/mu)-1i*bn1*sqrt(k+1)*sin(theta/2)*exp(-1i*phi)*sin(mu*t)/mu);

>>

Answer 1

[VBBV]

clear;
clc;
syms k
Delta=0;
chi=0;
theta=0;
alpha=5;
phi=0;
bn=exp(-0.5*alpha^2)*(alpha^k)/sqrt(gamma(k+1));
bn1=exp(-0.5*alpha^2)*(alpha^(k+1))/sqrt(gamma(k+2));
t = 0:pi/100:2*pi;
Gamma=chi*k^2-0.5*Delta;
Wn=0.5*Delta-chi*k;
mu=sqrt((0.5*Delta-chi*k)+k+1);
An=exp(-1i*Gamma*t).*(bn*cos(theta/2).*(cos(mu*t)-1i*Wn.*sin(mu*t)./mu)-1i*bn1*sqrt(k+1)*sin(theta/2)*exp(-1i*phi).*sin(mu*t)./mu);
zz=real(An).^2+2*imag(An);
y1 = symsum(zz,k, 0, 20);
plot(t,y1,'r','Color',[0.5 0 0.8])

[VBBV]

Matlab uses elementwise operator ./ .* for multiplying or dividing one or more multidimensonal vectors