He also showed that the roots of a cubic equation can be derived by means of the infinitesimal calculus.
Each of those is a root of a quadratic equation in terms of the one before.
After the elimination is done, one has to find the real roots of a single variable equation numerically.
He also obtained some evaluations of the number of real roots of an equation.
Originally Galois used permutation groups to describe how the various roots of a given polynomial equation are related to each other.
Any complex number which is a root of an equation where are integers will, said Dedekind, be called an algebraic number.
Stone gives an example of this: when computing the roots of a quadratic equation the computor must know how to take a square root.
Every root of a polynomial equation whose coefficients are algebraic numbers is again algebraic.
He used what would later be known as the "Ruffini-Horner method" to numerically approximate the root of a cubic equation.
This section describes how the roots of such an equation may be computed.