u=x(z+y) z=sin(x+z) 求二阶偏导数σ2u／σxσy

u=x(z+y) z=sin(x+z) 求二阶偏导数σ2u／σxσy 已知x/(y+z+u)=y/(z+u+x)=z/(u+x+y)=u/(x+y+z)求(x+y)/(z+u)+(y+z)/(x+u)+(z+u)/(x+y)+(u+x)/(y+z) x/(y+z+u)=y/(z+u+x)=z/(u+y+x)=u(x+y+z)求(x+y)/(z+u)+(y+z)/(y+x)+(z+y)/(x+y)+(u+x)/(z+y) u=x(z+y) z=sin(x+y) 求二阶偏导数σ2u／σxσy 帮忙求一个全微分u=2sin（x+2y-3z）-（ x+2y-3z ）.z=z（x,y） z=f(u) u=x/y,求x*∂z/∂x +y*z∂z/∂y u=arctan(x-y)^z偏导数u/z只求关于Z的求导, 求全微分 u=x^y^z (x+y-z)(x-y+z)= 已知x+y+z=π,证明sin(x+y)+sin(y+z)+sin(z+x)≥sin2x+sin2y+sin2z 设函数f(u)具有二阶导数,而z=f((e^x)*sin(y))满足方程d^2(z)/d^2(x^2)+d^2(z)/d(y^2)=e^(2*x)*z,求f(u).令u=e^x*siny,则z=f(u)∂z/∂x=∂z/∂u*∂u/∂x=f'(u)*e^x*siny=uf'(u),∂²z/∂x²=∂(u X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 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)=? 已知z=z(x,y)由sin(xy)+z^2=sin(x+z)确定,求z关于x的偏导数 设x+y+z=11求函数u=2x*x+3y*y+z*z的最小值 C语言求三角函数f(x,y,z)=sin(x)/(sin(x-y)*sin(x-z))+sin(y)/(sin(y-x)*sin(y-z))+sin(z)/(sin(z-x)*sin(z-y))代码#include #include double fun(double x,double y,double z){double a,b,c,sum;a=sin(x)/(sin(x-y)*sin(x-z));b=sin(y)/(sin(y-x)*sin(y-z));c (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值