# Logarithmic differentiation

From AMS Glossary

## logarithmic differentiation

Finding derivatives by taking the logarithm of both sides of an equation and then differentiating.

In meteorology this process is applied, for example, to the equation of state for a perfect gas, giving or to the Poisson equation for potential temperature, giving where

*P*is pressure, ρ density,*T*temperature, θ potential temperature, and Κ Poisson's constant.