\subsection{ROOT\_VAL Operator}
The {\tt ROOT\_VAL} operator takes a single univariate polynomial as
argument, and returns a list of root values at system precision (or
greater if required to separate roots). It is used with the syntax
\begin{verbatim}
ROOT_VAL(EXPRN:univariate polynomial):list.
\end{verbatim}
For example, the sequence
\begin{verbatim}
on rounded; root_val(x^3-x-1);
\end{verbatim}
gives the result
\begin{verbatim}
{0.562279512062*I - 0.662358978622, - 0.562279512062*I
- 0.662358978622,1.32471795724}
\end{verbatim}