早教吧作业答案频道 -->数学-->
1.计算(x^-1+y^-1/x^-1-y^-1)-(4/x^-1*y-xy^-1)结果不含负整数指数幂2.已知x(x-1)-(x^2-y)=-3,求x^2+y^2-2xy的值挺急的
题目详情
1.计算(x^-1+y^-1/x^-1 - y^-1)-(4/x^-1*y- xy^-1)结果不含负整数指数幂 2.已知x(x-1)-(x^2-y)=-3,求
x^2+y^2-2xy的值
挺急的
x^2+y^2-2xy的值
挺急的
▼优质解答
答案和解析
(x^-1+y^-1/x^-1 - y^-1)-(4/x^-1*y- xy^-1)
=(1/x+1/y)/(1/x-1/y)-4/[y(1/x)-x(1/y)]
分子和分母都乘以xy,有
=(y+x)/(y-x)-4xy/(y²-x²)
=(y+x)(y-x)/(y-x)(y-x)-4xy/(y²-x²)
=(y+x)²/(y²-x²)-4xy/(y²-x²)
=(x²+2xy+y²-4xy)/(y²-x²)
=(x²-2xy+y²)/(y²-x²)
=(x-y)²/(y-x)(y+x)
=(y-x)/(y+x)
2.x(x-1)-(x^2-y)=-3
x²-x-x²+y=-3
y-x=-3
x^2+y^2-2xy=(x-y)²=9
=(1/x+1/y)/(1/x-1/y)-4/[y(1/x)-x(1/y)]
分子和分母都乘以xy,有
=(y+x)/(y-x)-4xy/(y²-x²)
=(y+x)(y-x)/(y-x)(y-x)-4xy/(y²-x²)
=(y+x)²/(y²-x²)-4xy/(y²-x²)
=(x²+2xy+y²-4xy)/(y²-x²)
=(x²-2xy+y²)/(y²-x²)
=(x-y)²/(y-x)(y+x)
=(y-x)/(y+x)
2.x(x-1)-(x^2-y)=-3
x²-x-x²+y=-3
y-x=-3
x^2+y^2-2xy=(x-y)²=9
看了 1.计算(x^-1+y^-1...的网友还看了以下:
高一数学指数,对数函数!要详细过程!请指教!一.求下列函数的定义域.1.y=根号下的1-3^x2. 2020-04-27 …
1.当-2≤x≥2时,求函数y=x²-2x-3的取值范围2.当x≥0时,求函数y=-x(2-x)的 2020-05-16 …
线性规划数学题:实数x,y满足x-y+1≤0,x>0,y≤2,若实数x,y满足x-y+1≤0,x> 2020-05-16 …
1.已知x+y=6,xy=7,求(3x+y)+(x+3y) 2.(1-1/2)(1-1/31.已知 2020-06-27 …
设f(u)有一阶连续偏导数,f(0)=2,且z=xf(y/x)+yf(y/x)满足∂z/∂x+∂z 2020-07-08 …
ax^2-1/9ab^2-ab-2a^2b-a^3b3a^2bc^3+6ac^2-9acdx^n+ 2020-07-22 …
实数x,y满足x-y+1≤0,x>0,y≤2(1)若z=y/x,求z的取值范围(2)若z=x平方+ 2020-07-26 …
求高次和差公式推导,重金酬谢x^n-y^n=(x-y)[x^(n-1)+x^(n-2)y+x^(n- 2020-10-31 …
用隐函数求导法则对x^y=y^x求导为什么会得出x^2=y^2x^y=y^x用隐函数求导法则yx^( 2020-10-31 …
看不懂下题过程,从“x,y是实数”开始,求解y+x-4=2√(x^+9),平方得x^+2(y-4)x 2020-10-31 …