Previous Up Next

2.24.18  Compute with the exact root of a polynomial : rootof

Let P and Q be two polynomials given by the list of their coefficients then rootof(P,Q) denotes the value P(α) where α is the root of Q with largest real part (and largest imaginary part in case of equality).
In exact computations, Xcas will rewrite rational evaluations of rootof as a unique rootof with degree(P)<degree(Q). If the resulting rootof is the solution of a second degree equation, it will be simplified.

Example
Let α be the root with largest imaginary part of Q(x)=x4+10x2+1 (all roots of Q have real part equal to 0).


Previous Up Next