Fri, 28 Apr 2023
A nice illustration popped up on Math SE this morning. OP asks:
Shortly afterward a comment from PrincessEev said, opaquely:
Uh, they are? It wasn't obvious to me. I mean, I think I see why the eigenvalues must be zero, without doing the calculation. But where did this example come from?
But then later they redeemed themselves by adding another comment:
I understand now! Yeah, I could have thought of that, but didn't. So the second comment actually taught me something, not what the answer is, which not very useful, because who cares?, but how to find the answer, which contains knowledge that might be generally useful.