Roots of Solvable Polynomials of Prime Degree

An explicit formula for the most general root of a solvable polynomial of prime degree is stated and proved. Such a root can be expressed rationally in terms of a single compound radical determined by the roots of a cyclic polynomial whose degree divides μ − 1, where μ is the prime. The study of such formulas was initiated by a formula of Abel for roots of quintic polynomials that are solvable, and was carried forward by Kronecker and a few others, but seems to have lain dormant since 1924. A formula equivalent to the one given here is contained in a paper [14] of Anders Wiman in 1903, but it seems to have been forgotten.