The presentation of Lagrange´s equations in introductory robotics courses

The topic of Lagrange´s dynamic equations is presented in a fashion suitable for introductory robotics courses. The development of the material does not rely on either principles of virtual work or variational calculus. The thrust of the demonstration is that, given dynamic for a rigid body, one can always manipulate the equations to show that the equations depend exclusively on the difference between the total kinetic and potential energies of the system