Using the laws of exponents, we can derive what fractional and
negative powers mean:
a0=a1−1=a1a1=1, as long as a≠0.
a−n=a0−n=a0an=1an,
as long as a≠0.
(ap/q)q=ap, so
ap/q=q√ap=(q√a)p,
as long as a≥0.
Notice: the expression 00, as well as negative powers of 0 are not defined, and so are fractional powers of negative numbers, since ap may not have a q-th root.