(微分)10的負1/y次方的微分?

x=10^(-1/y)
In x=(-1/y) In 10
In x=-(y^-1) In 10
(1/x)(dx/dy)=(y^-2) In 10
dx/dy=x(y^-2)In 10
dx/dy=[10^(1/y)](y^-2) In 10

Sol
題目改為10^(－1/x) 的微分
y=10^(－1/x)
lny=－(1/x)ln10
dy/dx
=(dy/dlny)*(dlny/dx)
=(dlny/dy)^(－1)*[－d(1/x)/dx]ln10
=－(1/y)^(－1)*(－1/x^2)*ln10
=y*ln10/x^2
=10^(－1/x)ln10/x^2