计算行列式x,y,x y;y,x y-搜答案-智慧作业帮

等于1/X*（X-Y）

y/(x²-xy)+2/(y-x)-x/(y²-xy)=[y²+2(-xy)+x²]/(x²y-xy²)=(x-y)²/[(x-y

这是一个初中竞赛题目与高中的主要运用公式x^3-y^3=(x-y)(x^2+xy+y^2)x^3+y^3=(x+y)(x^2-xy+y^2)其中(x-y)(x^2+xy+y^2)=x(x^2+xy+y

c1+c2+c32(x+y)yx+y2(x+y)x+yx2(x+y)xyr3-r2,r2-r12(x+y)yx+y0x-y0-yy-x--此时用对角线法则得=2(x+y)[x(y-x)-y^2]=-2

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

3xy[2xy-x（y-2）+x]＝3xy[2xy-xy+2x+x]=3xy(xy+3x)=3x²y²+9x²y

xy0...000xy...00........000...xyy00...0x最后一行最后多了一个y.看行列式中元素的规律,主对角线上都是x,主对角线右侧都是y,其余都是0.按第1列展开,行列式=x

(X+Y)(X^2-XY+Y^2)=(x*x^2-x*xy+x*y^2)+(x^2y-xy^2+y^3)=x^3+y^3这个是立方和的公式,再给你一个x^3-y^3=(X-Y)(X^2+XY+Y^2)

xyx+yyx+yxx+yxyc1+c2+c32(x+y)yx+y2(x+y)x+yx2(x+y)xyr3-r2,r2-r12(x+y)yx+y0x-y0-yy-x--此时用对角线法则得=2(x+y)

这题少括号了吧.

【x²+xy/（x-y）】/【xy/（x-y）】=【x²（x-y）/（x-y）+xy/（x-y）】/【xy/（x-y）】={【x²（x-y）+xy】/（x-y）}/【xy

（xy-y^2)÷x-y/xy=y(x-y)×[xy/(x-y)]=xy²

[(x²+2xy+y²)/(xy-y²)][(x²-2xy+y²)/(xy+y²)]={(x+y)²/[y(x-y)]}{(x-y

=x^3-y^3-(x^3+y^3)=-2y^3^3表示三次方

直接分开相乘结果为xy（x^-1)+xy(y^-1)]=x+y

（xy-x²）乘（x-y）分之xy=-x(x-y)乘[(x-y)分之xy]=-x²y

将第二三行分别加到第一行,第一行都为2*（x+y）,提取,得2*（x+y）*{1,1,1;y,x+y,x;x+y,x,y};再将第一行分别乘以（-y）、（-x-y）加到二三行,得2*（x+y）*{1,

原式＝x⑶+x²y+xy²-x²y-xy²-y⑶=x⑶-y⑶

x-y/xy-y^2计算

解(x-y)/(xy-y²)=(x-y)/y(x-y)=1/y

直接展开：=3yx^2+3xy^2-x^3-y^3-3yx^2-3xy^2=-x^3-y^3再问：这个我知道呀，没有简便的方式吗？