The function powpoly(poly, var) returns a formal power series equivalent to poly.

Thus, for all i, the ith coefficient of the power series returned is coeff(poly, var, i).

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

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

$t≔\mathrm{powpoly}\left(2x^5+4x^4-x+5\,x\right)\:$

$\mathrm{tpsform}\left(t\,s\,5\right)$

$5-s+4s^4+O\left(s^5\right)$

$\mathrm{tpsform}\left(t\,s\,4\right)$

$5-s+O\left(s^4\right)$