# Loxodrome question

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1. Oct 21, 2014

### kkz23691

Hello,

On this site http://mathworld.wolfram.com/SphericalSpiral.html
the loxodrome is given by

(1)
$x=cos(t)cos(c)$
$y=sin(t)cos(c)$
$z=-sin(c)$
(oblate spheroidal coordinates in the limit when the spheroid is actually a sphere. A bit unusual though, putting a "minus" sign in z )

and
(2)
$c\equiv tan^{-1}(at)$

Why did they choose this second condition in this form oo)?
It must be a matter of definition, judging by the "$\equiv$" sign in it. But why exactly this and not something else oo)?

Would anyone know? Thanks!

2. Oct 26, 2014