$\mathcal{l}$

${\displaystyle {\int }_0^{\text{2π}}{P}_{\mathcal{l}}\left[\cos \left(\phi -{\phi }^{\prime }\right)\right]\text{d}{\phi }^{\prime }}$

0

$2\text{π}$

1

0

2

$\frac{1}{2}\text{π}$

3

0

4

$\frac{9}{32}\text{π}$

5

0

6

$\frac{25}{128}\text{π}$

7

0