User b c - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-22T03:26:58Z http://mathoverflow.net/feeds/user/5840 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/23478/examples-of-common-false-beliefs-in-mathematics/23492#23492 Answer by B C for Examples of common false beliefs in mathematics. B C 2010-05-04T21:56:59Z 2010-05-04T22:15:34Z <p>$0^0$ is undefined.</p> <p>EDIT: People write things like $\sum_{k=0}^\infty x^k$ all day, but somehow $x=k=0$ is still scary when written as $0^0$.</p> http://mathoverflow.net/questions/23478/examples-of-common-false-beliefs-in-mathematics/23492#23492 Comment by B C B C 2010-05-04T22:26:44Z 2010-05-04T22:26:44Z @Kevin: yes. @Qiaochu: it is a belief incompatible with &quot;$\sum_{k=0}^\infty x^k$ is defined for $x=0$&quot; which is usually considered true.