Talk:Tractrix

Old posts

Why is there no mention of its more friendly name 'Hundkurve'?

what are the functions ch(x) and ctg(x) used in the 'basis of the tractrix' section? are these cosh(x) and cot(x)? I've never seen those before, I don't want to change them. Monguin61 (talk) 05:26, 17 March 2009 (UTC)

This actual German page hints the Hundekurve is actually the more general conchoid of Nicomedes. 142.177.24.163 04:53, 19 Aug 2004 (UTC)

The tractrix is not a conchoid. -phma 17:43, 28 Aug 2004 (UTC)

See de:Hundekurve - depending on the problem, the trival name "dog's curve" is either a conchoid, a tractrix, or a (straight) curve of pursuit --W!B: 01:31, 18 November 2005 (UTC)

I think that using a "dummy variable" t instead of x in the expression

$y=\int _{x}^{a}{\frac {\sqrt {a^{2}-t^{2}}}{t}}\,dt$

would be a less confusing notation. Mark.howison 03:47, 14 December 2005 (UTC)

Merger

Yes to merging tractrice into this page. Richard Pinch 06:31, 9 October 2006 (UTC)

Pseudo-latin terms

I removed the terms tractendus and tractens for the pulling resp. pulled object. For one, they should be reversed (-endus is passive while -ens is active), for another the correct classical latin forms would be trahens and trahendus. And anyway, it's been a while that latin was the lingua franca of mathematics. HannsEwald 11:23, 18 January 2007 (UTC)

Error in function

The inverse hyperbolic secant function does NOT have the tractrix as graph. It has a vertical tangent line, not a horizontal one, where it hits the x-axis. The correct function can be found for example in Spivak's comprehensive introduction to differential geometry, volume 3, page 239. Duvel2011 (talk) 22:33, 23 March 2011 (UTC)

The section "Mathematical derivation" is not explained well

The section Mathematical derivation leaves out a crucial step in the derivation. Although some mathematically adept readers can fill in that step, that does not justify omitting it.50.205.142.35 (talk) 12:46, 13 February 2020 (UTC)

 Fixed, I hope. D.Lazard (talk) 15:21, 13 February 2020 (UTC)