I first saw this in UW's challenge of the week (if I remember correctly), where they used to post a nice math puzzle every week and give the winners (drawn at random from the correct solutions) a gift certificate to Baskin Robbins.
[That has now been discontinued and I believe the pages also have been taken down.]
Anyway, here is the puzzle.
If x,y>0 are real numbers, show that
xy+yx>1
[That has now been discontinued and I believe the pages also have been taken down.]
Anyway, here is the puzzle.
If x,y>0 are real numbers, show that
xy+yx>1