Descartes' rule of signs [SEP] named after
Descartes' rule of signs
In mathematics, Descartes' rule of signs, first described by René Descartes in his work "La Géométrie", is a technique for getting information on the number of positive real roots of a polynomial. It asserts that the number of positive roots is at most the number of sign changes in the sequence of polynomial's coefficients (omitting the zero coefficients), and that the difference between these two numbers is always even. This implies in particular that, if this difference is zero or one
to Mathematics Genealogy Project, as of February 2013, he has over 66 thousand academic descendants, out of the total 170 thousand mathematicians in the database.
Contributions.
He was the first scientist to use the reactive force of water and constructed the first water-jet, the Segner wheel, which resembles one type of modern lawn sprinkler. Segner, also produced the first proof of Descartes' rule of signs. Historians of science remember him as the father of the water turbine. The lunar crater Segner is named after