Comment by roenxi

Those definitions of exp are all immediately obvious and nearly the definition of textbook, every university calculus course covers them. That is the issue with defining interesting as novel - nothing generally known is novel any more. And they don't require any special maths - sum_{i=0}^\infty z^n/n! is literally just multiplication and addition.

The long and short of it is it just isn't possible to tell someone that their problem isn't interesting. Interest isn't an inherent property of an equation, it is the state of mind of the person looking at the equation. And in this case the x+y/xy is a classic interesting puzzle despite (really because of) how well known the solution is.