[davidbyttow]

Intentional. The idea is that 1/1 could be a fluke. :-)

[wging]

For x == 0, this also blows up.

And for x > 1, which base you use matters. E.g. if x == y == 2,

    >>> from math import log,e
    >>> 100 * log(2,2)
    100.0
    >>> 100 * log(2,e)
    69.31471805599453
    >>> 100 * log(2,10)
    30.102999566398115

I'm aware it's meaningless, but which base did you intend? :)