Question

由方程xy-lny=0所确定的隐函数的导数dy/dx

Answer 1

(xy)'-(lny)'=0
x'y+xy'-d(lny)/dy*dy/dx=0
y+xy'-1/y*y'=0
y+(x-1/y)y'=0
y'=y/(1/y-x)
y'=y^2/(1-yx)