Can someone explain this?(Taylor polynomials)

1. Nov 10, 2004

NINHARDCOREFAN

For function f(x)=1/(1+x^2), calculate Taylor polynomials for the 2nd and 4th degree about the point a=0.

P2 = 1-x^2;
P4 = 1-x^2+x.^4

for 2nd degree I got -2x/[(1+x^2)^2]
for 4th degree I got 12x/[(1+x^2)^4]

2. Nov 10, 2004

Muzza

But neither of your solutions are polynomials?

3. Nov 10, 2004

NINHARDCOREFAN

Why aren't they?

4. Nov 11, 2004

Muzza

Last edited: Nov 11, 2004