Hello Hello!

I've been doing some homework and I really don't understand a few things.

Can anyone explain to me how the Descartes' Rule and Fundamental theorem can be used to determine the number of complex roots (in a polynomial)?

Examples would be absolutely stellar!

Also, does anyone know what setting a "good window" (on a graphing calculator) is?

and what features of a polynomial should be given?

Thank you! :]