Re: [GiNaC-list] series((x+x^2)^2,x,0) is broken

On 6/24/23 18:15, Vitaly Magerya wrote:

...

If a series A starts with x^n, then the series 1/A *ends*, not starts, with 1/x^n.

OK, sorry, that's not corect. Let me say it differently:

series(sin(x)-x, x, 2) == Order(x^2)

This does not mean

1/series(sin(x)-x, x, 2) == Order(x^-2),

because

series(1/(sin(x)-x), x, -2) == -6/x^3 + Order(x^-2)

But sin(x)-x starts with (-1/6)*x^3 which is of Order(x^3). -richy.