a;

kill(all)$

van=facebook.com/LearningCalculus$

f(f(x))=a^x;

f(x):=(1/log(b))^x;

f(f(x))=a^x;

fpprec:20;

bfloat(%e);

h(b):=b^b-%e;

newton(t):=bfloat(subst(t,b,b-h(b)/diff(h(b),b)))$

newton(1.7632228343518967102b0);

f(f(f(x)));

h(b):=b^b^b-%e;

newton(t):=bfloat(subst(t,a,a-h(a)/diff(h(a),a)))$

newton(1.6010751539237287793b0);