You're perfectly right.
Works like a charm!

Cheers
--
AP

"Jerry W. Lewis" a écrit dans le message de
news: ...
You can accomplish the same thing without the Solver Add-In by using
Tools|Goal Seek. The precision of the numerical solution is controlled by
Tools|Options|Calculation|Maximum Change.

An nth degree polynomial has n roots, some of which may be complex. Since
all coefficients are real, complex roots must come in pairs. Therefore
there
are either 0, 2, or 4 real roots of your polynomial. If you plot the
polynomial over the range -1 to 4, you will see that there real roots with
-1<root<-0.5 and 3<root<3.5. The change in slope between 1 and 2 implies
that the other two roots must be complex. Which of the two real roots
Solver/Goal Seek finds will be determined by the initial guess that you
supply.

Jerry

"MartinW" wrote:

Thanks Ardus. That sounds like exactly what I need unfortunately solver
is
an add-in that requires the CD-ROM to install and I haven't got my disc
here at the moment. I'll try it tomorrow when I have the disc and report
back how it goes.

Cheers
Martin