  We prove the classical result, which goes back at least to Fourier, that a
polynomial with real coefficients has all zeros real and distinct if and only
if the polynomial and also all of its nonconstant derivatives have only
negative minima and positive maxima. Intuition for the result, involving
illuminating pictures, is described in detail. The generalization of Fourier's
theorem to certain entire functions of order one (which is conjectural)
suggests that the official description of the Riemann Hypothesis Millennium
Problem incorrectly describes an equivalence to the Riemann Hypothesis. The
paper is reasonably self-contained and is intended be accessible (possibly with
some help) to students who have taken two semesters of calculus.
