summation operation in matlab

hello, i am trying to write a code to implement the summation operation but having errors the equation is below. my code is

A=rand(1,10);
N = 6;
for b = 1:N
    syms A;
  Pb = (A.^N/factorial(N)) / symsum ((A.^i)/(factorial(i)),i,0,N);

   % Bp = (Toi.^N)/(factorial(N)) / symsum(Toi.^[0:N]./ factorial([0:N]));
  end

and i keep getting this error

??? Error using ==> factorial at 17
N must be a matrix of non-negative integers.

Error in ==> ERLANGB_TEST at 7
  Pb = (A.^N/factorial(N)) / symsum ((A.^i)/(factorial(i)),i,0,N);

thanks for your anticipated help.

[Salaheddin Hosseinzadeh]

What is this in your quesion?

% Bp = (Toi.^N)/(factorial(N)) / symsum(Toi.^[0:N]./ factorial([0:N]));
end

thanks

[joe khese]

that is the code i wrote to implement the equation above but i keep getting this error N must be a matrix of non-negative integers.

Answer 1

[Mischa Kim]

Joe, use

 syms A ii
 N   = 6;
 Pb  = A^N/factorial(N)/(symsum(A^ii/factorial(ii),0,N)); % symbolic expression
 sPb = subs(Pb,A,3);                 % substitute 3 for A to get numeric result

[Mischa Kim]

What release are you working with?

What happens when you replace in the equation

 factorial(N)

by

 sym('N!')

Answer 2

[joe khese]

thanks Mischa. I tried what u suggested but still getting the same error. N must be a matrix of non-negative integers.

Answer 3

[Marta Salas]

You must define i as a symbolic variable too, otherwise i is defined as the sqrt(-1)

syms A i
N = 6;
Pb = (A.^N/factorial(N)) / symsum ((A.^i)/factorial(i),i,0,N);