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19 Elliptic IntegralsLegendre’s Integrals19.3 Graphics
Figure 19.3.6 (See in context.) 3D Help
See accompanying text
Figure 19.3.6: Π⁡(ϕ,2,k) as a function of k2 and sin2⁡ϕ for −1≤k2≤3, 0≤sin2⁡ϕ<1. Cauchy principal values are shown when sin2⁡ϕ>12. The function tends to +∞ as sin2⁡ϕ→12, except in the last case below. If sin2⁡ϕ=1 (>k2), then the function reduces to Π⁡(2,k) with Cauchy principal value K⁡(k)−Π⁡(12⁢k2,k), which tends to −∞ as k2→1−. See (19.6.5) and (19.6.6). If sin2⁡ϕ=1/k2 (<1), then by (19.7.4) it reduces to Π⁡(2/k2,1/k)/k, k2≠2, with Cauchy principal value (K⁡(1/k)−Π⁡(12,1/k))/k, 1<k2<2, by (19.6.5). Its value tends to −∞ as k2→1+ by (19.6.6), and to the negative of the second lemniscate constant (see (19.20.22)) as k2(=csc2⁡ϕ)→2−. 3D Help