what's the density distribution inside a dark matter halo that allows flat rotation curves? how does that correspond to the NFW-profile shape and what's the reason that the size of the galactic disk is roughly equal to the NFW scale radius?
bonus question: can you show using a power series that
for two square, real-valued, commuting matrices $A$ and $B$, i.e. $\left[A,B\right]=0$. what changes if the two matrices are non-commuting?