Talk:Proofs

Just needed to get all this text out of my head to concentrate on other stuff. — Alonso del Arte 23:28, 4 September 2011 (UTC)

eqnarray*

There is something called an "equation array" that they often use on PlanetMath to neatly line up equations. Is that available under MediaWiki? I would like to use it for the amusing proof that 1 = 2. — Alonso del Arte 23:20, 5 September 2011 (UTC)

Do you mean this (used on Fibonacci numbers)

:<math>\begin{array}{rcrcrcrcrcrcr}
f(x)         & = & F_0 x^0 & + & F_1 x^1 & + & F_2       x^2 & + & \cdots & + & F_i               x^i & + & \cdots \\
x f(x)       & = &         &   & F_0 x^1 & + & F_1       x^2 & + & \cdots & + & F_{i-1}           x^i & + & \cdots \\
x^2 f(x)     & = &         &   &         &   & F_0       x^2 & + & \cdots & + & F_{i-2}           x^i & + & \cdots \\
(x+x^2) f(x) & = &         &   & F_0 x^1 & + & (F_0+F_1) x^2 & + & \cdots & + & (F_{i-1}+F_{i-2}) x^i & + & \cdots \\
             & = &         &   &         &   & F_2       x^2 & + & \cdots & + & F_i               x^i & + & \cdots \\
\end{array}</math>

where {rcrcrcrcrcrcr} tells the text alignment for each column (e.g. right, center,) giving

${\begin{array}{rcrcrcrcrcrcr}f(x)&=&F_{0}x^{0}&+&F_{1}x^{1}&+&F_{2}x^{2}&+&\cdots &+&F_{i}x^{i}&+&\cdots \\xf(x)&=&&&F_{0}x^{1}&+&F_{1}x^{2}&+&\cdots &+&F_{i-1}x^{i}&+&\cdots \\x^{2}f(x)&=&&&&&F_{0}x^{2}&+&\cdots &+&F_{i-2}x^{i}&+&\cdots \\(x+x^{2})f(x)&=&&&F_{0}x^{1}&+&(F_{0}+F_{1})x^{2}&+&\cdots &+&(F_{i-1}+F_{i-2})x^{i}&+&\cdots \\&=&&&&&F_{2}x^{2}&+&\cdots &+&F_{i}x^{i}&+&\cdots \\\end{array}}$

— Daniel Forgues 06:25, 6 September 2011 (UTC)