I've seen that Q before. Probably the 2009 CSSA.
Here's an interesting Q: Prove 3/4+5/36+7/144+9/400+11/900+...= 1
EDIT: Noticed previous Q not solved yet.
As before, eq'n of tangent is y=x/e
Now due to geometry of figure (ie. tangent lies above curve), (x/e) >= ln x (with equality occuring...