Question

unit quaternions, rotations, and regular octahedron...

In the symmetry group of the regular octahedron what is the unit quaternion that represents 90 degree rotation about the semi x -axis lambda i , lambda > 0 The rotation appears to be counterclockwise to an observer at point A

Answer 1

I have a vector of just i when I am the observer at point A

Answer 2

so u is a unit quaternion llull = 1 where u = alpha + v
-1< alpha < 1

alpha = cos theta

Answer 3

so if I have a 90 degree rotation already given.. wouldn't that be
\[2 \theta = 90\]
theta = 45 degrees
and then it will be \[\frac{1}{\sqrt{2}}\]

Answer 4

so my equation would be \[u = \frac{1}{\sqrt{2}} = \lambda i \]

Answer 5

/ffffffffffff \[u = \frac{1}{\sqrt{2}}+\lambda i\]

Answer 6

http://math.stackexchange.com/questions/1273575/finding-the-unit-quaternion-for-the-regular-octahedron

Answer 7

just what is it talking about!!!! I attempted it, but not sure if it's right

Answer 8

What are you asking for?

Answer 9

here's the question :
In the symmetry group of the regular octahedron what is the unit quaternion that represents 90 degree rotation about the semi x -axis lambda i , lambda > 0 The rotation appears to be counterclockwise to an observer at point A

Answer 10

and I'm reading this paper too.. to try and get something out of it
http://www.math.unm.edu/~vageli/papers/rrr.pdf

Answer 11

hmmm a rotation about the x-axis by 90 degrees maps the figure to itself. wait.. go to that site and read pages 7 and 8. It has something similar to what I'm asking

Answer 12

I think the answer you're looking for is left multiply by "i". That's a unit quaternion that will rotate counter clockwise while looking from A.