Decades: 1230s 1240s 1250s 1260s 1270s - 1280s - 1290s 1300s 1310s 1320s 1330s
Years: 1283 1284 1285 1286 1287 - 1288 - 1289 1290 1291 1292 1293
Births
Deaths
... different cases: If the discriminant is zero, then there is a repeated solution x, and this solution is real. (Geometrically, this means that the parabola ...