1. The problem statement, all variables and given/known data My prof showed us the proof that sqrt2 is not a rational number. She said, however, that we haven't proved that it is irrational, because we haven't proved that sqrt2 exists. How would we go about proving this? 2. Relevant equations N/A 3. The attempt at a solution This isn't really a homework question, it's just curiosity. I think she said something about showing that sqrt2 is a solution to x^2 - 2 = 0, and that when you graph this function, it does indeed intersect the x-axis sqrt2. But that seemed a bit fishy (or incomplete, or something...) to me.