Rotation as a vector
29 March, 2001:
In response to the thread about "rotation as a vector," last addressed by :
Posted on: 02/09/01 11:42 PST
In reply to message no. 6049 by dr funda.
Let me first clear up some shoddy language usage.
The initial question asked:
"if rotation was a vector."
This question is unclear, for it should ask:
"which of angular
The quick answer is:
"the first is not."
A slightly longer answer would add:
"the second two are."
Longer again would say:
"go consult pp.324 - 325 of
Pure and Applied Mathematics,
HALSTEAD & HARRIS,
Macmillan & Co,
Melbourne, Australia, 1963"
On p.324, this text gives a cogent proof that for small angular displacement, a Pythagorean identity can apply for compounding angles in 3D, i.e.
A^2 = B^2 + C^2
An even longer answer adds:
"go consult p.296 - 300
Advanced Engin'g Mathematics,
John Wiley & Sons,
New York, USA, 1962"
Finally I would add:
"Both references, like the initial questioner, are also shoddy in using
the word as an unclear muddling of the three and
These are ancient texts I admit, from way back when I did my first tertiary
qualification, in the early 60's. More recent text incarnations will say
the same thing. Certain fundamentals will NEVER change, like Ohms Law.
I still possess every text from every course I have ever done,
with heavy marginal annotations, copious underlining, and now heavy
highlighting. Don't let anyone tell you that education is wasted.