POV-Ray : Newsgroups : povray.advanced-users : Stumped by desk lamp trig equation : Re: Stumped by desk lamp trig equation Server Time
2 Oct 2022 17:59:16 EDT (-0400)
  Re: Stumped by desk lamp trig equation  
From: kurtz le pirate
Date: 6 Aug 2022 13:32:06
Message: <62eea596$1@news.povray.org>
On 06/08/2022 18:24, Cousin Ricky wrote:
> I want to aim a desk lamp by specifying where it should point.  P(x,y)
> is where to aim the lamp, c is the length of the flexible part of the
> neck, a is an additional rigid distance to the central axis of the lamp
> hood, and f is the angle to bend the neck.  The initial equation was
> huge and ugly, but I managed to simplify it considerably, to this form:
> 
>   (x - c/f) * sin(f) + y * cos(f) = a
> 
> But now I'm stuck.  Variables a, c, x, and y are given, and I need to
> solve for f.  I plugged it into Wolfram Alpha, but it gave up.  I don't
> even know if a paid subscription would find a solution, and I would
> hardly use the service enough to justify a subscription anyway.  Does
> anyone have an idea of how to proceed with the equation?  Or should I
> gamble that Wolfram Alpha Pro can solve it and pay for one month?
> 

To test your equation, I replaced the a, c, x and y by numerical values.
Wolfram solve the equation but only numerically because apparently there
is not only one solution...

<https://www.wolframalpha.com/input?i=solve+++%283+-+4%2Fx%29+*+sin%28x%29+%2B+5+*+cos%28x%29+%3D+2>

Puzzled !

-- 
Kurtz le pirate
Compagnie de la Banquise


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.