ex machin_pi(int degr)
@{
symbol x;
- ex pi_expansion = series_to_poly(atan(x).series(x,degr));
+ ex pi_expansion = series_to_poly(atan(x).series(x==0,degr));
ex pi_approx = 16*pi_expansion.subs(x==numeric(1,5))
-4*pi_expansion.subs(x==numeric(1,239));
return pi_approx;