This is a list of divisions of the United States Army past and present. Armored, cavalry, and infantry are each numbered in their own sequences, and are thus grouped; the airborne and mountain divisions are numbered with the other infantry.
... expresses the explicit solution(s) x to the quadratic equation
<math>ax^2+bx+c=0</math>
in terms of the coefficients a, b and c, which are assumed to be real ...