The function negative(p) returns a formal power series where each coefficient is the negative of the corresponding coefficient in p.

The command with(powseries,negative) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{powseries}\right)\:$

$\mathrm{powcreate}\left(t\left(n\right)=\frac{t\left(n-1\right)}{n}\,t\left(0\right)=1\right)\:$

$s≔\mathrm{negative}\left(t\right)\:$

$\mathrm{tpsform}\left(s\,x\right)$

$\mathrm{-1}-x-\frac{1}{2}{x}^2-\frac{1}{6}{x}^3-\frac{1}{24}{x}^4-\frac{1}{120}{x}^5+O\left(x^6\right)$