1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/08 16:15:14
1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2
2.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值
3.A-(A^2B-2A^3B^2)\AB
4.0.5^(-1)-4*(-2)^(-2)+0.5^0-2^(-1)
2.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值
3.A-(A^2B-2A^3B^2)\AB
4.0.5^(-1)-4*(-2)^(-2)+0.5^0-2^(-1)
1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2
原式=4x^2+4xy+y^2-(2x^2+2xy-xy-y^2)-2(x^2-4y^2)
=3xy+10y^2
=3*0.5*(-2)+10*(-2)^2
=-3+40
=37
2.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值
(x^2-2x+1)+(y^2+2y+1)=0
(x-1)^2+(y+1)^2=0
x-1=0
y+1=0
x=1,y=-1
x^2008+y^2009=1-1=0
3.A-(A^2B-2A^3B^2)\AB
=A-AB(A-2A^2B)/AB
=A-(A-2A^2B)
=2A^2B
4.0.5^(-1)-4*(-2)^(-2)+0.5^0-2^(-1)
=2-4*1/4+1-1/2
=2-1+1/2
=3/2
原式=4x^2+4xy+y^2-(2x^2+2xy-xy-y^2)-2(x^2-4y^2)
=3xy+10y^2
=3*0.5*(-2)+10*(-2)^2
=-3+40
=37
2.已知X^2+Y^2-2X+2Y=-2,求代数值X^2008+Y^2009的值
(x^2-2x+1)+(y^2+2y+1)=0
(x-1)^2+(y+1)^2=0
x-1=0
y+1=0
x=1,y=-1
x^2008+y^2009=1-1=0
3.A-(A^2B-2A^3B^2)\AB
=A-AB(A-2A^2B)/AB
=A-(A-2A^2B)
=2A^2B
4.0.5^(-1)-4*(-2)^(-2)+0.5^0-2^(-1)
=2-4*1/4+1-1/2
=2-1+1/2
=3/2
先化简 再求值(x-2y)(2y-x)+(2x+y)(2x-y )-(x-2y)(2x+y) 其中x=-2,y=-1.
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