求函数Z=y/x,x=2,y=1,△x=0.1,△y=—0.2时的全增量和全微分

已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 设函数z=z(x,y),由方程x^y+y^x+z^x=1确定,求z对x,y的偏导 设x+y+z=11求函数u=2x*x+3y*y+z*z的最小值 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 高数求梯度设函数f(x,y,z)=(x-y)2+(y-z)2+(z-x)2,求gradf(x,y,z).我算对了吗 设函数z=z(x,y)由方程x^2+y^3-xyz^1=0确定,求z/x,z/y 多元复合函数微分法z=xyf(x/y,y/x) 求∂z/∂x.∂z/∂x=（∂/∂x)[xyf(x/y,y/x)]=yf(x/y,y/x)+xy(∂/∂x)f(x/y,y/x) 这部是怎么得到的啊?=yf(x/y,y/x)+xy[f①(x/y,y/x)(1/y)+f②(x/y,y/x)(-y/x^2)] 这 设方程z^y=y^x 确定函数z=z(x,y) ,求∂z/∂x 设函数f(x,y,z)=(x/y)^(1/z),求df(1,1,1) 设函数z=z(x,y),由方程z=e^(2x-3z)+2y确定,求∂z/∂x,∂z/∂y 已知函数f(x,y,z)=arcsin(x*x+y*y+lnz)求f(x-y,x+y,xz)? x+2y=3x+2z=4y+z 求x:y:z