You can prove this by showing, is impossible by squaring sides.
Show that is not in
Proof so far:
Let
Assume to the opposite that
Now, I want to take the trace of both side, but I'm really having problem with field trace, I don't know how to take the trace of neither side, are there any references I can find online that reteach me what trace is and how to compute it?
Thank you very much!