- #1

- 1

- 0

[tex]\frac{\partial^2}{\partial \theta^2}+\cot \theta \frac{\partial}{\partial \theta}[/tex]

Then, substitute

[tex]\mu = \cos \theta[/tex]

and the above is changed to

[tex](1-\mu^2)\frac{d^2}{d \mu^2}-2 \mu \frac{d}{d \mu}[/tex]

I don't know how the last expression is obtained.

Please, help me...