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问题: 如果虚数z满足z^3=8,那么z^3+z^2+2z+2的值是_____

如果虚数z满足z^3=8,那么z^3+z^2+2z+2的值是______

解答:

z^3-8=(z-2)(z^2+2z+4)=0 ==> 虚数z: z^2+2z+4=0
z^3+z^2+2z+2 =z^3+(z^2+2z)+2 = 8+(-4)+2 =6