ysinx=cos(x-y)同时求导数y'sinx+ycosx=(x-y)'sin(y-x)y'sinx+ycosx=(1-y')sin(y-x)y'sinx+ycosx=sin(y-x)-y'sin(y-x)y'sinx+y'sin(y-x)=sin(y-x)-ycosxy'[sinx+sin(y-x)]=sin(y-x)-ycosxy'=[sin(y-x)-ycosx]/[sinx+...