11.1.23  Coefficients of a polynomial defined by its roots

The pcoeff or pcoef command reconstructs a polynomial from its roots.

• pcoeff takes roots, a list of the roots of a polynomial P.
• pcoeff(roots) returns the monic polynomial having these roots, represented as the list of its coefficients in decreasing order.

Example

i.e. (x−1)(x−2)(x²)(x−3)=x⁵−6x⁴+11x³−6x².