Suspension Acoustics: An Introduction to the Physics of Suspensions

Written by a leading expert in the field, this book is an introduction to the physics of suspensions of bubbles, droplets, and solid particles in both gases and fluids.
The relevant differential equation here is (5.3.17), or
The solutions to this equation are the Legendre polynomials of the first and second kinds P n (x) and Q n (x), respectively. Explicit forms for low values of n are:
n=0
n=1
n=2
These recurrence relations are also satisfied by Q n .