是x²+3y²-4x+2y+13/3=0
(x²-4x+4)+3(y²+2y/3+1/9)=0
(x-2)²+3(y+1/3)²=0
所以x-2=y+1/3=0
x=2,y=-1/3
所以原式=1/2^(1/3(=1/2的立方根