Centuries: 2nd century - 3rd century - 4th century
Decades: 190s - 200s - 210s - 220s - 230s - 240s - 250s - 260s - 270s - 280s - 290s
Years: 240 241 242 243 244 245 246 247 248 249
Events:
... Generalizations The formula and its proof remain correct if the coefficients a, b and c are complex numbers, or mor ...