设xy+lnx-lny=o,则dy/dx=

问题描述:

设xy+lnx-lny=o,则dy/dx=

xy+lnx-lny=0
两边对x求导
(y+xy')+1/x-y'/y=0
y+1+(x-1/y)y'=0
y'=(y+1)/(1/y-x)
y'=y(y+1)/(1-xy)