[DevPlan]幂运算待完善
>> (1/2)^(2/3)
in> (1/2)^(2/3)
out> sqrtn(1,3)|sqrtn(4,3)
------------------------
>> (a/b)^(2/3)
in> (a/b)^(2/3)
out>
------------------------
Answer
>> (1/2)^(2/3)
in> (1/2)^(2/3)
out> sqrtn(1,3)|sqrtn(4,3)
------------------------
>> (a/b)^(2/3)
in> (a/b)^(2/3)
out>
------------------------