Reference Yoshikawa, Takeo (http://216.239.57.104/search?q=cache:iQJsXhA8SSwC:www.angelfire.com/dc/1spy/Yoshikawa+Takeo+Yoshikawa&hl=en&ie=UTF-8)
... 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 (but see below ...