RE: back to the well again... parallel trend lines

[john hamon <jhamon@xxxxxxxxxxx>]

thanks, gary!  i'll give it a try.  what a helpful group of people.

jh

-----Original Message-----
From: Gary Fritz [mailto:fritz@xxxxxxxx]
Sent: Thursday, January 04, 2001 10:16 AM
To: jhamon@xxxxxxxxxxx
Cc: omega-list@xxxxxxxxxx
Subject: RE: back to the well again... parallel trend lines


> i want to take a known trend line, pick a third point and draw a
> line through it that is parallel to the known trendline.  i
> apologize for the incoherent writing.  my brain is in programmer
> mode i guess. 

OK, try this:

theta = arctangent((X2-X1)/(Y2-Y1)), as before.

Third point is at X3,Y3.

Draw trendline from 
   X3-Z*cosine(theta),Y3-Z*sine(theta) 
to X3+Z*cosine(theta),Y3+Z*sine(theta) ?

I think that's about the simplest way.  If you're picky about where 
the endpoints of the parallel line end up, I'll let you do the trig 
this time.  :-)

Gary