The code returns a value in the form of "theta_3b(x, z) =.". How can I get this to return just theta_3b=

syms f g x y z

% % % % % Temperature Formula 3b % % % % %

theta_3b=0;

for n=0:25

t=0;

beta6 = (n*pi)/H;

eta6 = (((2*pi)/L)*(n+0.5));

mew6 = -1036;

lamda6 = (beta6.^2)+(eta6.^2)+(mew6.^2);

f(x,y,z) = sin(beta6*z).*cos(eta6*x).*sin(mew6*y).*cos(mew6*y);

C_nmp_numerator6 = int(int(int(f,z,[0 H]),y,[0 W]),x,[0 (L/2)]);

g(x,y,z) = ((cos(mew6*y)^2).*sin(mew6*y) - ((h/(k*mew6)).*(sin(mew6*y)^2).*cos(mew6*y)));

C_nmp_denominator6 = ((L*H)/8)* (int(g,y,[0 W]));

C_nmp6 = C_nmp_numerator6/C_nmp_denominator6;

theta_3b = theta_3b+(C_nmp6*(sin(beta6*z)*cos(eta6*x)*((cos(mew6*y)-(h/(k*mew6))*sin(mew6*y)))*exp(-(lamda6^2)*alpha*t)));

end

theta_3b = vpa(subs(theta_3b, {x,y,z}, {X,Y,Z}))