Path: news.mathworks.com!not-for-mail
From: <HIDDEN>
Newsgroups: comp.soft-sys.matlab
Subject: Re: sym and solve
Date: Mon, 16 Jan 2012 12:16:09 +0000 (UTC)
Organization: The MathWorks, Inc.
Lines: 11
Message-ID: <jf14e9$626$1@newscl01ah.mathworks.com>
References: <jeuvdg$l2f$1@newscl01ah.mathworks.com> <jevafr$m8f$1@newscl01ah.mathworks.com> <jevbn8$ppj$1@newscl01ah.mathworks.com> <jevfdc$6u2$1@newscl01ah.mathworks.com> <jevnlo$ef$1@newscl01ah.mathworks.com> <jf06ph$cce$1@newscl01ah.mathworks.com>
Reply-To: <HIDDEN>
NNTP-Posting-Host: www-06-blr.mathworks.com
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Trace: newscl01ah.mathworks.com 1326716169 6214 172.30.248.38 (16 Jan 2012 12:16:09 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Mon, 16 Jan 2012 12:16:09 +0000 (UTC)
X-Newsreader: MATLAB Central Newsreader 1187260
Xref: news.mathworks.com comp.soft-sys.matlab:754803

"Roger Stafford" wrote in message <jf06ph$cce$1@newscl01ah.mathworks.com>...
>  theta = atan2(t,s);
> ........
>  x1 = u*cos(theta)-v*sin(theta);
>  y1 = u*sin(theta)+v*cos(theta);
>  x2 = u*cos(theta)+v*sin(theta);
>  y2 = u*sin(theta)-v*cos(theta);
- - - - - - - - - -
  In that suggestion I made to you there really was no need for explicitly evaluating theta with 'atan2' and then finding cos(theta) and sin(theta).  I don't know why I did that.  It is much simpler to just use (s/a) in place of cos(theta) and (t/a) in place of sin(theta) in transforming (u,v) over to (x1,y1) and (x2,y2).

Roger Stafford