如果^2+(z)^2=ln dfrac (z)(x),则^2+(z)^2=ln dfrac (z)(x)( ).A.^2+(z)^2=ln dfrac (z)(x)B.^2+(z)^2=ln dfrac (z)(x)C.^2+(z)^2=ln dfrac (z)(x)D.^2+(z)^2=ln dfrac (z)(x)

设 ^2+(y)^2+(z)^2-4z=0, 求 dfrac ({a)^2z}(q{x)^2}

( A ) = (x,y,z)|{x)^2+(y)^2+(z)^2=(a)^2,zgeqslant 0} ( B ) = (x,y,z)|{x)^2+(y)^

1.设 ^2+(y)^2+(z)^2-z=0, 求 dfrac ({a)^2z}(a{y)^2}

球面^2+(y)^2+(z)^2+4x+6y+2z+10=0的球心坐标为A.^2+(y)^2+(z)^2+4x+6y+2z+10=0B.^2+(y)^2+(z)

16.设函数 z=z(x,y) 由方程 ^2+(y)^2+(z)^2-6z=0 确定,求 dfrac ({sigma )^2z}(sigma x{U)_(y)}

1.设 (x,y,z)=dfrac (z)({x)^2+(y)^2}, 则 df(1,2,1)= __

设(x,y,z)=(x)^2+(y)^3+z,求(x,y,z)=(x)^2+(y)^3+z,在点(x,y,z)=(x)^2+(y)^3+z,处沿方向(x,y,z

函数(z)=(x)^2+(y)^2i ( ).A.仅在(z)=(x)^2+(y)^2i上解析;B.在除(z)=(x)^2+(y)^2i之外的复平面上

6.函数 =ln ((x)^2+(y)^2+(z)^2) 在点 M(1,2,-2) 处的梯度 (|)_(M)= __

设数量场 =ln sqrt ({x)^2+(y)^2+(z)^2} 则rot(gradu) (1,0,1)1 ,= () .-|||-(A) dfrac (1)