Domain of f is x >= 0

Pardon my ignorance, but why is the function not defined for x < 0? At x = -1, is its value not 77? and . . Please help me to understand if I am overlooking something.

Nicholas Hu (talk)02:48, 1 November 2014

You are absolutely right! This works because of the odd denominator in the fractional power. I was confused because, in general, the n-th root of a negative number has n solutions, if you allow complex numbers. This is also the reason why google & wolframalpha etc tell you that (-1)^(2/7) is a complex number. None of that fanciness is necessary here, and your solution is very clear. Good job.

Bernhard Konrad (talk)20:02, 1 November 2014