kill(all)$
fpprintprec:4$

van=facebook.com/LearningCalculus$

f(x,y):=atan(x*y)$
float(f(11/10,8/10));

T(x,y):=taylor(f(x,y), [x,y], [1,1], 1)$
t(x,y):=''(T(x,y))$
factor(t(x,y));
float(t(11/10,8/10));

T(x,y):=taylor(f(x,y), [x,y], [0,0], 2)$
t(x,y):=''(T(x,y))$
t(x,y);
factor(t(x,y));
float(t(11/10,8/10));

T(x,y):=taylor(f(x,y), [x,y], [11/10,8/10], 1)$
t(x,y):=''(T(x,y))$
factor(t(x,y));
float(t(11/10,8/10));

kill(all);