Question

设y=y(x)是由方程e的y次方－xy=e所确定的隐函数,则导数dx分之dy=?

Answer 1

e^y-xy=e

e^y·dy/dx-(y+x·dy/dx)=0

e^y·dy/dx-y-x·dy/dx=0

(e^y-x)·dy/dx=y

dy/dx=y/(e^y-x)

dy/dx不能叫做dx分之dy,因为这是个导数符号,而不是分数!