Issue in term mismatch after finding roots

I aim having a mismatch error in the following code. The term1a works fine but I get no output from term1b, which I believe is causing my mismatch error. "In an assignment A(I) = B, the number of elements in B and I must be the same" referring to CB1(t)=Cb

      while n<22
      f=@(qn) tan(qn)-((3*qn./(3+alpha*(qn.^2))));
      r= fzero(f,pi/2*[n n+2].*(1+100*eps*[1 -1]));
      %term1=(6*alpha*(1+alpha)*exp(-Dall*(r.^2)*(t/(rS.^2))))/(9+9*(r.^2)*(alpha.^2));
      term1a=(6*alpha*(1+alpha)*exp(-Dall1*(r.^2)*(t/(rS.^2))))/(9+9*(r.^2)*(alpha.^2))
      term1b=((rS+.01)/rS)*(sin(qn.*rS./(rS+.01))/sin(qn))
      term2=term2+term1a.*term1b;
      n=n+2;
      end 

Cb1=(cAi/(1+alpha))*(1-term2);
CB1(t)=Cb1;

Answer 1

[Roger Stafford]

In the expression for 'term1b' you use the variable 'qn'. However, that appears to be the dummy argument for your function 'f'. Perhaps you need to replace that 'qn' with the root, 'r'.

Also you need to be sure that the variable 't' is a positive integer if it is to be used as an index in "CB1(t)=Cb1;".