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椭圆 Alpha 函数


椭圆 alpha 函数将第一类椭圆积分 K(k_r)第二类 E(k_r) 完全椭圆积分与椭圆积分奇异值 k_r 关联,关系如下

alpha(r)=(E^'(k_r))/(K(k_r))-pi/(4[K(k_r)]^2)
(1)
=pi/(4[K(k_r)]^2)+sqrt(r)-(E(k_r)sqrt(r))/(K(k_r))
(2)
=(pi^(-1)-4sqrt(r)q(dtheta_4(q))/(dq)1/(theta_4(q)))/(theta_3^4(q)),
(3)

其中 theta_3(q)Jacobi theta 函数,并且

k_r=lambda^*(r)
(4)
q=e^(-pisqrt(r)),
(5)

并且 lambda^*(r)椭圆 lambda 函数。椭圆 alpha 函数与椭圆 delta 函数的关系为

 alpha(r)=1/2[sqrt(r)-delta(r)].
(6)

它满足

 alpha(4r)=(1+k_(4r))^2alpha(r)-2sqrt(r)k_(4r),
(7)

并且有极限

 lim_(r->infty)[alpha(r)-1/pi] approx 8(sqrt(r)-1/pi)e^(-pisqrt(r))
(8)

(Borwein et al. 1989)。一些特定值 (Borwein 和 Borwein 1987, p. 172) 为

alpha(1)=1/2
(9)
alpha(2)=sqrt(2)-1
(10)
alpha(3)=1/2(sqrt(3)-1)
(11)
alpha(4)=2(sqrt(2)-1)^2
(12)
alpha(5)=1/2(sqrt(5)-sqrt(2sqrt(5)-2))
(13)
alpha(6)=5sqrt(6)+6sqrt(3)-8sqrt(2)-11
(14)
alpha(7)=1/2(sqrt(7)-2)
(15)
alpha(8)=2(10+7sqrt(2))(1-sqrt(sqrt(8)-2))^2
(16)
alpha(9)=1/2[3-3^(3/4)sqrt(2)(sqrt(3)-1)]
(17)
alpha(10)=-103+72sqrt(2)-46sqrt(5)+33sqrt(10)
(18)
alpha(12)=264+154sqrt(3)-188sqrt(2)-108sqrt(6)
(19)
alpha(13)=1/2(sqrt(13)-sqrt(74sqrt(13)-258))
(20)
alpha(15)=1/2(sqrt(15)-sqrt(5)-1)
(21)
alpha(16)=(4(sqrt(8)-1))/((2^(1/4)+1)^4)
(22)
alpha(18)=-3057+2163sqrt(2)+1764sqrt(3)-1248sqrt(6)
(23)
alpha(22)=-12479-8824sqrt(2)+3762sqrt(11)+2661sqrt(22)
(24)
alpha(25)=5/2[1-25^(1/4)(7-3sqrt(5))]
(25)
alpha(27)=3[1/2(sqrt(3)+1)-2^(1/3)]
(26)
alpha(30)=1/2{sqrt(30)-(2+sqrt(5))^2(3+sqrt(10))^2×(-6-5sqrt(2)-3sqrt(5)-2sqrt(10)+sqrt(6)sqrt(57+40sqrt(2)))×[56+38sqrt(2)+sqrt(30)(2+sqrt(5))(3+sqrt(10))]}
(27)
alpha(37)=1/2[sqrt(37)-(171-25sqrt(37))sqrt(sqrt(37)-6)]
(28)
alpha(46)=1/2[sqrt(46)+(18+13sqrt(2)+sqrt(661+468sqrt(2)))^2×(18+13sqrt(2)-3sqrt(2)sqrt(147+104sqrt(2))+sqrt(661+468sqrt(2)))×(200+14sqrt(2)+26sqrt(23)+18sqrt(46)+sqrt(46)sqrt(661+468sqrt(2)))]
(29)
alpha(49)=7/2-sqrt(7[sqrt(2)7^(3/4)(33011+12477sqrt(7))-21(9567+3616sqrt(7))])
(30)
alpha(58)=[1/2(sqrt(29)+5)]^6(99sqrt(29)-444)(99sqrt(2)-70-13sqrt(29))
(31)
=3(-40768961+28828008sqrt(2)-7570606sqrt(29)+5353227sqrt(58))
(32)
alpha(64)=(8[2(sqrt(8)-1)-(2^(1/4)-1)^4])/((sqrt(sqrt(2)+1)+2^(5/8))^4).
(33)

J. Borwein 编写了一个算法,该算法使用格基约减来提供 alpha(n) 的代数值。


另请参阅

第一类椭圆积分, 第二类椭圆积分, 椭圆积分奇异值, 椭圆 Lambda 函数

使用 Wolfram|Alpha 探索

参考文献

Borwein, J. M. and Borwein, P. B. Pi & the AGM: A Study in Analytic Number Theory and Computational Complexity. New York: Wiley, 1987.Borwein, J. M.; Borwein, P. B.; and Bailey, D. H. "Ramanujan, Modular Equations, and Approximations to Pi, or How to Compute One Billion Digits of Pi." Amer. Math. Monthly 96, 201-219, 1989.

在 Wolfram|Alpha 中被引用

椭圆 Alpha 函数

请引用为

Weisstein, Eric W. "椭圆 Alpha 函数。" 来自 MathWorld--Wolfram Web 资源。 https://mathworld.net.cn/EllipticAlphaFunction.html

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