مکانیک لاگرانژی

${\displaystyle L=T-V}$

${\displaystyle S={\int }_0^T(\frac{1}{2}m{\dot{x}}^2-V(x))dt}$

${\displaystyle \frac{\mathrm{\partial }L}{\mathrm{\partial }x}-\frac{d}{dt}\frac{\mathrm{\partial }L}{\mathrm{\partial }\dot{x}}=0}$

${\displaystyle m\ddot{x}=-\frac{\mathrm{\partial }V}{\mathrm{\partial }x}=F}$