8的1/3次方是多少？复数域中

(x+yi)^3=8(x,y属于R

(x^2-y^2+2xyi)(x+yi)=8

(x^3-y^3i+3x^2*yi-3xy^2)=8

x^3-3xy^2=8

3x^2*y-y^3=0

x=2,y=0

x=-1,y=根号3

x=-1,y=-根号3

z=-1+根号3

z=-1-根号3

z=2