Hi guys, I recently started reading/working through Scott Dodelson's Modern Cosmology in preparation for a Masters course I'm taking next year and one of the exercises has stumped me and (arghhh!) its not one of the solved ones in the back! It is in Chapter 4 (The Boltzmann equations) and is exercise 2. The exercise concerns the Boltzmann equation in the synchronous gauge. Does anyone know where I can get a solution from just so I can see how it's done! Thanks!