Is Simulink can call to a MATLAB Function, and the symbolic function and the 'subs' function can be included in the matlab function?

I want to use the simulink to call to the Matlab Function block. And want to use symbolic function and 'subs' function in the m.file. and the simulink program and the code of the m.file was attached on

function [x,time]=Steffensentt(delta_dot0,x0) coder.extrinsic('subs','syms','num2str','global','str2num');

syms f;syms f2;syms f3;syms f4;syms f5;syms f6;syms f7;

syms y;syms z;

f1='0.5*0.463^2*';

f2=num2str(delta_dot0);

f3='^2+(1-0.621)*(3.4e3^2/x^2*log(';

f4=num2str(delta_dot0);

f5='*x/3.4e3+1)-3.4e3*';

f6=num2str(delta_dot0);

f7='/x)';

f=[f1,f2,f3,f4,f5,f6,f7];

if(nargin==2)

    tol=1.0e-5;

end

time=0; err=0.1; x=x0;

while(err>tol)

    x1=x;
    y=subs(f,x1)+x1;
    z=subs(f,y)+y;
    x=x1-(y-x1)^2/(z-2*y+x1);
    err=abs(x-x1);
    time=time+1;  
end
err
x   
time;