In the novel Gravity's Rainbow by Thomas Pynchon, there is a chapter in which Slothrop (the main character) thinks about this equation:
$$\theta \frac{d^2\phi}{dt^2} + \delta^* \frac{d\phi}{dt} + \frac{\partial L}{\partial\alpha}(s_1-s_2)\alpha = -\frac{\partial R}{\partial\beta} s_3\beta\,.$$
It seems to be something to do with the V2 rocket, and yaw control. Does anyone recognise this equation from a book or research paper? What do the various variables stand for? He may have invented the equation, I suppose. How would one go about solving an equation like this? I find it strange that it contains both partial derivatives and total derivatives. However, there are equations in Hamiltonian mechanics like this.
Any help would be much appreciated. Thank you.