Recent content by elquin

In spherical coordinates, the operator is defined as \frac{\partial^2}{\partial \theta^2}+\cot \theta \frac{\partial}{\partial \theta} Then, substitute \mu = \cos \theta and the above is changed to (1-\mu^2)\frac{d^2}{d \mu^2}-2 \mu \frac{d}{d \mu} I don't know how the last...