Why does it says makeFhandle,Not enough input arguments. at DF=(z)What can I do?

R=518;
T=223;
p=65000000;
Tc=191;
Pc=4580000;

a=(0.427)*((R^2)*(Tc^2.5))/Pc;

b=(0.0866)*((R*Tc)/Pc);

z=input('Input initial guess- ');
sym v;
fun= @(v) p-(R*T./(v-b)) +( a./(v.*(v+b)*sqrt(T)));
A=matlabFunction(diff(fun,v));

F=fun(z);
DF=A(z);

n=1;
Ea=100;


while abs((Ea))>=10^(-5) 
    disp(F);
    disp(DF)
    zi=z-(F/DF);
    Ea=((zi-z).*100)/zi; 
    z=zi;
    n=n+1;
end
disp(zi);
disp(Ea);
disp(n);

[Walter Roberson]

sym v;

should be

syms v;

[Thanuja Bandara]

Thank you for your comment. Still the same error occurs.

[Walter Roberson]

I did not have any trouble after I made that change

which MATLAB version are you using?

[Thanuja Bandara]

I am using matlab 2013. I think that was the problem.

A=matlabFunction(diff(fun(v)))

After changing it like that I got the answer. Thank you very much for your help.