** suivant:** Truncate of order n
** monter:** Polynomials
** précédent:** Exact roots of a
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##

Coefficients of a polynomial defined by its roots : `pcoeff pcoef`

`pcoeff` (or `pcoef`) takes as argument a list of
the roots of a polynomial *P*.

`pcoeff` (or `pcoef`) returns a univariate polynomial having
these roots,
represented as the list of it's coefficients by decreasing order.

Input :
`pcoef([1,2,0,0,3])`

Output :
`[1,-6,11,-6,0,0]`

i.e.
(*x* - 1)(*x* - 2)(*x*2)(*x* - 3) = *x*5 - 6*x*4 + 11*x*3 - 6*x*2.

giac documentation written by Renée De Graeve and Bernard Parisse