Decades: 1160s 1170s 1180s 1190s 1200s - 1210s - 1220s 1230s 1240s 1250s 1260s
Years: 1206 1207 1208 1209 1210 - 1211 - 1212 1213 1214 1215 1216
Births
Deaths
... characteristic 2, the element 2a is zero and it is impossible to divide by it.) The symbol <math>\pm \sqrt {b^2-4ac}</math> in the formula should b ...