Digital Library of Mathematical Functions
About the Project
NIST
19 Elliptic IntegralsLegendre’s Integrals19.3 Graphics

Figure 19.3.5 (See in context.)

See accompanying text
Figure 19.3.5: \mathop{\Pi\/}\nolimits\!\left(\alpha^{2},k\right) as a function of k^{2} and \alpha^{2} for -2\leq k^{2}<1, -2\leq\alpha^{2}\leq 2. Cauchy principal values are shown when \alpha^{2}>1. The function is unbounded as \alpha^{2}\to 1-, and also (with the same sign as 1-\alpha^{2}) as k^{2}\to 1-. As \alpha^{2}\to 1+ it has the limit \mathop{K\/}\nolimits\!\left(k\right)-(\mathop{E\/}\nolimits\!\left(k\right)/{%
k^{{\prime}}}^{2}). If \alpha^{2}=0, then it reduces to \mathop{K\/}\nolimits\!\left(k\right). If k^{2}=0, then it has the value \frac{1}{2}\pi/\sqrt{1-\alpha^{2}} when \alpha^{2}<1, and 0 when \alpha^{2}>1. See §19.6(i).