User fubini - MathOverflowmost recent 30 from http://mathoverflow.net2013-05-22T07:06:53Zhttp://mathoverflow.net/feeds/user/9601http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/40337/ingenuity-in-mathematics/40377#40377Answer by Fubini for Ingenuity in mathematicsFubini2010-09-28T19:51:02Z2010-09-28T19:51:02Z<p>Linear algebra proof of Binet's formula for Fibonacci numbers.</p>
<p>Fibonacci numbers satisfy</p>
<p>$\begin{pmatrix} 1 & 1 \\ 1 & 0 \end{pmatrix}^{n} = \begin{pmatrix} F_{n+1} & F_{n} \\ F_{n} & F_{n-1} \end{pmatrix}$</p>
<p>Diagonalize the matrix on left.</p>