Lenses Equation - Reiterating for 5 Lenses.

I am trying to reiterate the equation to find the position of an image for a single lens up to 5 lenses. The equation for a single lens is , where , and . As the equation is iterated forwards, A, B and C change and become more complicated, hence the reqierment for MATLAB. When i run my code I get the 'Index exceeds matrix dimensions" error. Any help would be greatly appreciated, thank you in advance.

n = 5;                     % No. of Lenses 
x0 = 0;                    % Source Position [cm]
xi = (1:n);                % Create Array
xi(1) = 3.9;               % Lens Position [cm]
xi(2) = 10.9;
xi(3) = 23.1;
xi(4) = 31.8;
xi(5) = 41.2;

f = (1:n);                 % Focal Lengths [cm]
f(1) = 0.5;  
f(2) = -1.0;
f(3) = 2.0;
f(4) = -2.5;
f(5) = 1.0;

a = (xi);
b = f + xi;
c = xi - f;

A = zeros(1,n);  % Create Array of Zeros
B = zeros(1,n);
C = zeros(1,n);


xi1 = (A(1)-(B(1)*x0))/(C(1)-x0);

for i = 2,n;
    
    A(i) = (((a(i).^2)*C(i-1))-(b(i)*A(i-1)))/((n(i)*C(i-1))-B(i-1));
    
    B(i) = ((-b(i)*B(i-1))-(a(i).^2))/(((a(i).^2)*C(i-1))-B(i-1));
    
    C(i) = ((c(i)*C(i-1))-A(i-1))/((c(i)*C(i-1))-B(i-1));
   
end 

Image = (A(n)-(B(n)*x0))/(C(n)-x0)

[Torsten]

An array named "n" does not exist in your code (A(i) = .../((n(i)...)

[Stephen23]

There is a bug is where you try to access n(i) (but n is a scalar, you probably meant to use another variable here).

Note that the vector defintions are far too complex. Simpler:

xi = [3.9,10.9,23.1,31.8,41.2];
f  = [0.5,-1.0, 2.0,-2.5, 1.0];
n = numel(f);

[Billy Le Grave]

Brilliant, Thank you very much!