kill(all)$

fpprec:60$

van=facebook.com/LearningCalculus$

newton(t):=bfloat(subst(t,x,x-f(x)/diff(f(x),x)));

f(x):=x^x^x^16-16;
g(x):=x^x^x^12;

f(1.189207115002721066717499970560475915292972092463817413019b0);

newton(1.189207115002721066717499970560475915292972092463817413019b0);

g(%);