8.840 Let us set
where λ is a real parameter, in the defining differential equation 8.700 1 for associated Legendre functions. We then obtain the differential equation of the so-called conical functions. A conical function is a special case of the associated Legendre function. However, the Legendre functions
have certain peculiarities that make us distinguish them as a special class—the class of conical functions. The most important of these peculiarities is the following
8.841 The functions ...