Testwiki:Reference desk/Archives/Mathematics/2014 October 28

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October 28

Catalan number

Can someone explain Catalan numbers more simplistically than our article does? Why they work the way they do for example. Thanks, Dismas|^(talk) 08:53, 28 October 2014 (UTC)

This pdf might help you. It explains the connections between various problems whose solutions involve the Catalan numbers, and derives some of the properties of Catalan numbers. A key property is the recurrence relation

$C_{n+1}=\sum _{m=0}^n{C}_m{C}_{n-m}$

Gandalf61 (talk) 17:40, 31 October 2014 (UTC)

Situations where indeterminate forms are NOT considered indeterminate

The article indeterminate form says 0 time infinity is indeterminate. However, in the Extended real number line article, it says that for some purposes, 0 times infinity is unambiguously 0, and thus not indeterminate. Can anyone edit the indeterminate form article to make it include situations like these?? Georgia guy (talk) 18:17, 28 October 2014 (UTC)

There's nothing to edit. Yes, sometimes it's useful to define $0\times \mathrm{\infty }=0$, but not in the context of evaluating limits.--80.109.80.31 (talk) 19:16, 28 October 2014 (UTC)