[Jprogramming] A plane rotation

[David Lambert]

Thank you Kip.  I now understand the problem being solved.  Are there 
examples showing when this is useful?  Quite true that the product of 
slopes of perpendicular lines is _1 is useful.

On 02/19/2016 01:16 AM, programming-request at forums.jsoftware.com wrote:
> Date: Fri, 19 Feb 2016 00:16:08 -0600
> From: Kip Murray<thekipmurray at gmail.com>
> To:"programming at jsoftware.com"  <programming at jsoftware.com>
> Subject: Re: [Jprogramming] A plane rotation
> Message-ID:
> 	<CAOfWorgxTjE91bvKBu99kjvJUDxEuyH60iemRP6eWKgODsvEHA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> In your example, 0 1 is the polynomial coefficients for the straight line
> being rotated.  In usual math notation this is the line y = x = 0 + 1 x .
> When you rotate this line by 1p1 radians about the origin 0 0 you get the
> same straight line, described by 0 1 which is the answer given.  (I am
> "cleaning", of course.)
>
> Also when you consider the straight line y = 1 + 2x (described by 1 2) you
> notice the point 0 1 is on this line so when you rotate this line by 1p1
> radians about the point 0 1 you get the same line, described by the answer
> 1 2 .
>
> It helps to draw pictures of the indicated straight lines.  Hope this helps.
>
> --Kip