k T ∂ ln g ( r 12 ) ∂ r 1 = − ∂ U ( r 12 ) ∂ r 1 − ρ ∫ [ ∂ U ( r 13 ) ∂ r 1 ] g ( r 13 ) g ( r 23 ) d r 3 {\displaystyle kT{\frac {\partial \ln g(r_{12})}{\partial r_{1}}}={\frac {-\partial U(r_{12})}{\partial r_{1}}}-\rho \int \left[{\frac {\partial U(r_{13})}{\partial r_{1}}}\right]g(r_{13})g(r_{23})~dr_{3}}
![{\displaystyle kT{\frac {\partial \ln g(r_{12})}{\partial r_{1}}}={\frac {-\partial U(r_{12})}{\partial r_{1}}}-\rho \int \left[{\frac {\partial U(r_{13})}{\partial r_{1}}}\right]g(r_{13})g(r_{23})~dr_{3}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/5b167052e06908379493b10e24e616712dab5542)