Z=ln (tan(x/y))和u=(x/y)^x的偏导数怎么求?

Z=ln (tan(x/y))和u=(x/y)^x的偏导数怎么求? 偏导数z=ln tan x/y 帮帮忙拜托啦u=ln(x^y乘y^z乘z^y)求du 求证tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-a)tan(z-x) u=ln(1/(x+√（y^2+z^2))),求u对x、u对y、u对z的偏导数,是u=ln(x+√（y^2+z^2))。没有分之1。 求导数 y=ln tan x 求导 y=ln(tan(x/2)) 已知x/z=ln(z/y),求z对x和y的偏导. 求证tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-z)tan(z-x)tan(x-y)+tan(y-z)怎么化成tan〔（x-y）+(y-z)〕? 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) 高数 设函数u=f(x,y,z),其中z=ln√(x^2+y^2),求(αu/αx)和(αu/αy) 三角函数（请写出过程）求证：tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-z)tan(z-x) 如何证明 tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-z)tan(z-x) 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) 设z=uv,u=e^(x+y),v=ln(xy)求dy 设有数量场u=ln(x^2+y^2+z^2),则div(gradu)= 设z=ln(x^z×y^x),求dz 求函数u=ln(2x+3y+4z^2)的全微分du