A double pendulum is a pendulum with another pendulum attached to its end, and is a simple physical system[?] that exhibits rich dynamic behavior[?]. The double pendulum is governed by very complicated formulas that can be found here (http://scienceworld.wolfram.com/physics/DoublePendulum). The double pendulum relates to:
... the usual form of the quadratic formula is not ideal. See Loss of significance for details.
Derivation
The quadratic formula is derived by the method of completing the ...