A multiple independently targetable re-entry vehicle, or MIRV, is a collection of nuclear weapons carried, usually ten or twelve warheads at a time, on a single intercontinental ballistic missile, allowing a single launched missile to strike a handful of targets, and allowing a few missiles to strike several targets redundantly.
... that when computing roots numerically, the usual form of the quadratic formula is not ideal. See Loss of significance for details.
Derivation
The quadratic formula ...