曲线 ) (x)^2-(y)^2+(z)^2=0 z=1 .

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

以曲线 ) z=(x)^2+2(y)^2 z=2-(x)^2 .B 、 ) z=(x)^2+2(y)^2 z=2-(x)^2 .以曲线在平面上的投影曲线

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)

设I为空间曲线 ) (x)^2+(y)^2+(z)^2=(R)^2 x+y+z=0-|||-B πR 2-|||-C 2πR 3-|||-D 2πR 2

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

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)}

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

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

12.设方程 +sqrt ({x)^2+(y)^2+(z)^2}=sqrt (2) 确定了函数 =z(x,y), 则z(x,y)-|||-在点 (1,0,-1)

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