(xy-1) (xy)^2-1当x,y趋于1时的极限-搜答案-搜搜考试网

[XY(2X-Y)的平方-(-XY的二次方)的二次方]除以8XY=[(2x-y)²-xy³]÷8=[（-2/3-1）²+1/3*1]÷8=（25/9+1/3）÷8=28/

简单啊就1啊再问：为什么再答：你把一带进去-3xy和3xy就抵消了啊所以式子里就不含xy项了啊

1/2≥(2/xy)^2==》√2/2≥|2/xy|==》√2≤|xy/2|==》2√2≤|xy|==》xy≤-2√2或2√2≤xy

1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a

原式=x2+（3k+6）xy-2y2-1，因为不含xy项，故3k+6=0，解得：k=-2．

(x+y-2xy)(x+y-2)+(1-xy)^2=(x+y)^2-2(1+xy)(x+y)+4xy+1-2xy+x^2y^2=(x+y)^2-2(1+xy)(x+y)+(1+xy)^2=(x+y)^

3xy[2xy-x(y-2)+x-1]=3xy(2xy-xy+2x+x-1)=3xy(xy+3x-1)=3x^2y^2+9x^2y-3xy

需要满足-2mxy-1/3xy=0即可由上式可得m=-1/6

-2kxy+1/2xy=0.k=1/4

5x^2y/-1/2xy*3xy^2

5x^2y/-1/2xy*3xy^2=-7.5x²y²

3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2

m=3

=3x^2y-2xy^2+2(xy-3/2x^2y)-xy+3xy^2=3x^2y+xy^2+2xy-3x^2y-xy=xy+xy^2=3*(-1/3)+3*1/9=-2/3

因式分解xy²-2xy+x+2y-1解xy²-2xy-y²+x+2y-1=xy²-2xy+x-y²+2y-1=x(y²-2y+1)-(y&#

-2kxy-3xy+(1/2)xy-x+8=[-2k-(5/2)]xy-x+8-2kxy-3xy+(1/2)xy-x+8中不含xy项则xy项前的系数为0-2k-(5/2)=0解得k=-5/4所以k=-

=(x²y²-4-x²y²-xy+4)/(-2xy)=-xy/(-2xy)=1/2

y^3+xy^2+2xy+x^2-1=(x+y-1)(x+y^2+y+1)再问：烦写出过程再答：

2(xy-5xy的平方)-(3xy的平方-xy)＝2xy-10xy的平方-3xy的平方＋xy＝3xy-13xy的平方当x=-1,y=1时,原式＝-3＋13＝10

原式=x2-2y2+（-3k+3）xy+1，∵此代数式不含有xy项，∴-3k+3=0，解得k=1．

[(xy+2)(xy-2)-2x的平方y的平方+4]÷（-xy)当x=10,y=25分之1=[x^2y^2-4-2x^2y^2+4]÷（-xy)=[-x^2y^2]÷（-xy)=xy=10*1/25=