Apparently gcalctool computes fractional powers by way of logarithms. Unfortunately this fails if the base is 0 (the result should always be 1, unless the exponent is 0, in which case it may be undefined, though gcalctool says 0^0=1). For example 0^(2/3) = 1, but gcalctool complains "Logarithm of zero is undefined" (which is correct in the reals, since in y = b^x, for any fixed b != 0 the limit of x as y approaches 0 is negative infinity). Perhaps this should be a special case.

Forwarded from downstream (Ubuntu) https://bugs.launchpad.net/ubuntu/+source/gcalctool/+bug/668512