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
(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