kill(all)$

fpprintprec:4$

van=facebook.com/LearningCalculus$

f(x):= sin(x)-cos(x)$

fp(x):=''(diff(f(x),x));

sin(x)+cos(x)=0;

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

newton(2.0);newton(%);newton(%);

f(%);

float(sqrt(2));

float(fp(3*%pi/4));