Revision as of 07:36, 15 August 2018 edit Audriusa (talk \| contribs) Extended confirmed users, Pending changes reviewers 5,621 edits →Recovering the axis-angle representation ← Previous edit		Revision as of 17:28, 19 November 2018 edit undo Ybungalobill (talk \| contribs) 211 edits →Recovering the axis-angle representation Next edit →
Line 889: == Recovering the axis-angle representation == From the definition looks like the angle is 2*arccos(q_r). Why it is now a different expression including atan? Is it a different angle now? Is it w no longer cos(w/2)? : <math>2 \arccos(q_r)</math> is correct only assuming a unit length quaternion, and has stability issues near <math>q_r = \pm 1</math>. Using the two-argument arg-tangent yields the correct angle for any non-zero quaternion in a numerically stable fashion. [[User:Ybungalobill\|bungalo]] ([[User talk:Ybungalobill\|talk]]) 17:28, 19 November 2018 (UTC)

Talk:Quaternions and spatial rotation: Difference between revisions