What does $QAQ^{-1}$ actually mean? - Mathematics Stack Exchange I'm self-learning Linear Algebra and have been trying to take a geometric approach to understand what matrices mean visually I've noticed this matrix product pop up repeatedly and can't seem to de
abstract algebra - Prove that 1+1=2 - Mathematics Stack Exchange Possible Duplicate: How do I convince someone that $1+1=2$ may not necessarily be true? I once read that some mathematicians provided a very length proof of $1+1=2$ Can you think of some way to