A device included in or attached to a nuclear weapon system to preclude arming and/or launching until the insertion of a prescribed discrete code or combination. It may include equipment and cabling external to the weapon or weapon system to activate components within the weapon or weapon system.
... These solutions are also called the roots of the equation. The formula reads
<math>
x=\frac{-b \pm \sqrt {b^2-4ac}}{2a}
</math>
The term b2 – 4ac ...