当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值
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当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值
当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值
当x=-2,y=2/3求3y^4-4x^2y-4y^4+2x^2y-x^2y的值
先化简:3y^4-4x^2y-4y^4+2x^2y-x^2y==-y^4-3x^2y
再将x=-2,y=2/3代入,得-(2/3)^4-3*(-2)^2*(2/3)=-8又16/81
3y^4-4x^2y-4y^4+2x^2y-x^2y=-y^4-3x^2y=-(2/3)^4-3*(-2)^(4/3)=-16/81-6* 2^(1/3)