Descartes's rule of signs
Des·cartes's rule of signs
(ˈ)dā¦kärts-,
-kȧts-
: a rule of algebra: in an algebraic equation with real coefficients, F(x) = 0, arranged according to powers of x, the number of positive roots cannot exceed the number of variations in the signs of the coefficients of the various powers and the difference between the number of positive roots and the number of variations in the signs of the coefficients is even
Word History
Etymology
after René Descartes †1650 French philosopher and mathematician