How to resolve this error:Error using ==> sym.sym>notimplemented at 2514 Function 'le' is not implemented for MuPAD symbolic objects. Error in ==> sym.sym>sym.le at 825 notimplemented('le'); Error in ==> nrm_prog1 at 17 while abs((x0--x)/x)*100<=5

I am geeting following error for the program

fun=input('enter the function= ')
f1=inline(fun);
f1d=diff(f1(x))
fd=inline(f1d);
x0=input('Enter the initial value of x:');

x=x0-(f1(x)/fd(x));

while abs((x0-x)/x)*100<=5
    x0=x;
    x=x0-(f1(x)/fd(x));
    if x==x0
        break
    end
end

[muna padhy]

Problem resolved with following statement x=x0-(f1(x0)/fd(x0));