Help with symbolic variables

Hello,

I have the following to calculate associated legendre polynomials (in terms of angles: http://en.wikipedia.org/wiki/Associated_legendre_polynomials#Reparameterization_in_terms_of_angles)

%Calculating associated legendre polynomials %Using Rodriguez formula

 syms z theta
 m = 0;
 l = 0;

 for i = 1:10

 Pl(i,:) = (inv((2^l)*factorial(l)))*diff(((z^2 - 1)^l),l);
 Plm(i,:) = ((-1)^m)*((sin(theta))^m)*diff(Pl(i,:),m);
 Plm(i,:) = subs(Plm(i,:), z, cos(theta));

 l = l + 1;
 end

I am struggling to find the way to replace the symbolic variable theta with a vector containing numerical values.

Any help would be greatly appreciated.

Tom