Método de Newton Raphson en Scilab

function y=f(x)
y=exp(-x)-log(x);
endfunction

function y=df(x)
y=-exp(-x)-1/x;
endfunction

function x=newtonraphson(x0,tol);
i=1;
ea(1)=100;
x(1)=x0;
while abs(ea(i))>=tol;
    x(i+1)=x(i)-f(x(i))/df(x(i));
    ea(i+1)=abs((x(i+1)-x(i))/x(i+1)*100);
    i=i+1;
end
printf(' i  \t      X(i)      Error aprox (i) \n');
for j=1:i;
    printf('%2d \t %11.7f \t %7.3f \n',j-1,x(j),ea(j));
end
endfunction