Decades: 1240s 1250s 1260s 1270s 1280s - 1290s - 1300s 1310s 1320s 1330s 1340s
1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
Births
Deaths
... y2. Since "2xy" in this case is (b/a)x, we must have y = b/(2a), so we add the square of b/(2a) to both sides, ...