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<spanclass="git-revision-date-localized-plugin git-revision-date-localized-plugin-date"title="April18, 202518:42:14">April18, 2025</span>&emsp;

<spanclass="git-revision-date-localized-plugin git-revision-date-localized-plugin-date"title="April22, 202501:19:59">April22, 2025</span>&emsp;

<li>Cassini's identity:</li>

<divclass="arithmatex">$$F_{n-1} F_{n+1} - F_n^2 = (-1)^n$$</div>

<p>This can be proved by induction. A one-line proof by Knuth comes from taking the determinant of the 2x2 matrix form below.</p>

<li>The "addition" rule:</li>

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