No idea why this happened. Perhaps Math.Pow(x,y) was implemented as 2**(y*log2(x)) without writing special code to deal with the case where x is negative real and y is integer?
In fairness, the general power function might well be complicated. Dealing with fractional base and exponent, signs (-1^2 makes sense but -1^0.5 doesn't in real numbers). I don't know how that works in code but I can see how this gremlin sneaks in.
I don't see how it gets past the test suite though.
I don't see how it gets past the test suite though.