求∫(y^2+z^2)dx+(x^2+y^2)dy+(x^2+y^2)dz沿C的线积分求∫(y^2+z^2)dx+(x^2+z^2)dy+(x^2+y^2)dz沿C的线积分C是半球x^2+y^2+z^2=2ax,z>0和圆柱x^2+y^2=2bx,0

x+y+z=0,x^2+y^2+z^2=1求dx/dz 设x+y^2+z=ln(x+y^2+z)^1/2,求dz/dx x+y^2+z=ln (x+y^2+z)^1/2 求dz/dx z=x^2-y/x+y,而y=2x-3,求dz/dx. 设由方程x+2y+z=e^(x-y-z)确定的隐函数为z=z(x,y),求d^2z/dx^2 微积分...设z=z(x,y)是方程^2+y^2+z^2=y*e^z确定的隐函数,求dz.2x/(y*e^z-2z) dx + 2y/(y*e^z-2z) dy 设有方程x+y^2+z^2=2z,求dz/dx dz/dy 设u=xz,其中Z=Z(x,y)是由方程x平方z+2y平方z平方+y=0确定,求du/dx f(x,y)=exp(-(x+y)) x>0 y>0 求Z=(X+Y)/2的概率密度.为什么其密度不等于∫f(x,2z-x)dx?（上下线是2z 0） 证明yz(2x+y+z)dx+xz(x+2y+z)dy+xy(x+y+2z)dz为全微分,并求原函数 求方程组dx/dt=2x-y+z ,dy/dt=x+2y-z ,dz/dt=x-y+2z的通解 设z=f(x,y)=arctanx/y ,y=√(x^2+1) ,求dz/dx 设 Z=x^2+y^2 x^2+2y^2+3z^2=20 求dy/dx ; dz/dx. 知道的回答下,x+y+z=0,x^2 + y^2 +z^2 = 1求：dy/dx,dz/dx f(x,y)=exp(-(x+y)) x>0 y>0 求Z=(X+Y)/2的概率密度.为什么不能所求密度不等于 ∫f(x,2z-x)dx? z=f(x,y)=x^3 + x^2 * y + x^2 ln(2+y)+e^(x+5) *y 求导数 dz/dx 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