1. The problem statement, all variables and given/known data A popular model for the mass distribution in a spheroid (such as a bulge) is the Hernquist model, with density ρ(r) = M(total)*a / 2πr(a+r)^3 M(total) is the total mass. a is constant with dimensions of length. Derive the enclosed mass M(r) 3. The attempt at a solution I am completely unsure on how to go about doing this? Any help is appreciated!