I managed to get the vector part right.
But how do I use the hint?
If someone has the time, I'd really appreciate it.
Let be the inverse of stereographic projection from to the equatorial hiperplane . Show that for every vector exists such that
The solution must rely on the following hint: the vector part of is , where .
I can't even get this vector part right..
As always, thanks for all the hints and help.
I will continue to work on it and post if I get anything.
(If it matters, it's not homework or exam question, just exercise.)