Emperor Richū (履中天皇) was the 17th imperial ruler of Japan. No firm dates can be assigned to this emperor or to his reign, but he is believed to have ruled the country during the early 5th century CE.
... 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 (but see ...