Talk:Weitzenböck's inequality

Graphic available

A GFDL-compatible illustration for this subject is available here: http://demonstrations.wolfram.com/WeitzenboecksInequality/ --Pleasantville (talk) 20:15, 6 March 2008 (UTC)

Reason for removing third proof

Currently (and in its present form here since April 2009), the article says

=== Third method ===

It can be shown that the area of the inner Napoleon's triangle, which must be nonnegative, is:

${\frac {1}{6}}(a^{2}+b^{2}+c^{2}-4{\sqrt {3}}\,\Delta ),$

so the expression in parentheses must be greater than or equal to 0.

But this doesn't agree with Mathworld's formula http://mathworld.wolfram.com/InnerNapoleonTriangle.html for the area of the inner Napoleon triangle, except when the original triangle is equilateral. Since the proof uses a wrong formula, the proof is wrong. Loraof (talk) 23:05, 26 June 2015 (UTC)

first proof is an interpretation, not a proof.

The first proof states that the Weitzenbock quantity, left minus right of inequality, is nonnegative because it is the area of an associated triangle (the "inner napoleon triangle"). This is an interpretation of the inequality, not a proof. To make it a proof one would have to show that the inside Napoleon triangle has a constant orientation relative to the triangle (e.g. as the vertices are moved around) which could be complicated to do. 73.149.246.232 (talk) 05:49, 27 February 2020 (UTC)

third and fourth proofs

The 3rd and 4th proofs are totally inscrutable, hard to decipher. Consider revising or removing.Toolnut (talk) 08:26, 19 April 2020 (UTC)