**e.g.** `((-27)^(2/3))^(3/2) = -27 or 27?` see [Limits_of_powers](https://en.wikipedia.org/wiki/Exponentiation#Limits_of_powers)
e.g.
((-27)^(2/3))^(3/2) = -27 or 27?see Limits_of_powers