clc
f1=@(x) exp(-x)-x;
f1d=@(x) -exp(-x)-1;

function yy=nraphson(f,fd,x0,es,imax,ea)
  iter=0;
  xr=x0;
  while (ea>es) &&(iter<=imax)
     xrold=xr;
     xr=xrold-f(xrold)/fd(xrold);
     iter=iter+1;
     if ne(xr,0)
       ea=abs((xr-xrold)/xr)*100;
     end
  end
    yy=xr;
end

fplot(f1,[0 1],'b')
grid on;
r1=nraphson(f1,f1d,0.25,0.01,5,2.6);
fprintf("El valor de la raiz es = %f \n",r1)