given i² = j² = k² = -1 = i*j*k therefore i = j*k = -k*j j = k*i = -i*k k = i*j = -j*i I see how we arive at i = j*k, b/c i² = i*j*k, so i*i/i = i*j*k/i, and finally i = j*k. But I don''t see how you get the sign when you revert the order of multiplication. FYI, I''m getting this out of Andre Lamothe''s great new book. I still can''t find (in this 1700 pg book) where he show you how to use quaternions for camera manipulation.

i = j*k
j*i = j*j*k
j*i = -k
-j*i = k
k = -j*i

(etc)