arithmetic–geometric mean identities

E157393

Arithmetic–geometric mean identities are a collection of formulas and relationships that express various mathematical constants and special functions in terms of the arithmetic–geometric mean of two numbers.

All labels observed (5)

How this entity was disambiguated

Statements (49)

Predicate Object
instanceOf mathematical identity collection ⓘ
result in analysis ⓘ
special function identity ⓘ
field mathematical analysis ⓘ
number theory ⓘ
special functions ⓘ
hasKeyFormula K(1/\sqrt{2}) = \frac{\Gamma(1/4)^{2}}{4\sqrt{\pi}} ⓘ
K(k) = \frac{\pi}{2\,\operatorname{AGM}(1,\sqrt{1-k^{2}})} ⓘ
\frac{1}{\operatorname{AGM}(1,\sqrt{1-k^{2}})} = \frac{2}{\pi}K(k) ⓘ
\int_{0}^{\infty}\frac{dx}{\sqrt{(x^{2}+a^{2})(x^{2}+b^{2})}} = \frac{\pi}{2\,\operatorname{AGM}(a,b)} ⓘ
\int_{0}^{\pi/2}\frac{d\theta}{\sqrt{a^{2}\cos^{2}\theta + b^{2}\sin^{2}\theta}} = \frac{\pi}{2\,\operatorname{AGM}(a,b)} ⓘ
\operatorname{AGM}(1,1/\sqrt{2}) = \frac{\Gamma(1/4)^{2}}{4\sqrt{\pi^{3}}} ⓘ
\operatorname{AGM}(1,\sqrt{1-k^{2}}) = \frac{\pi}{4}\,\frac{1}{K(k)} ⓘ
\operatorname{AGM}(1,\sqrt{1-k^{2}})\,\operatorname{AGM}(1,\sqrt{1-k'^{2}}) = \frac{\pi}{2} with k'^{2}=1-k^{2} ⓘ
\operatorname{AGM}(a,b) = \frac{\pi}{4}\,\frac{a}{K(k)} with k^{2}=1-\left(\frac{b}{a}\right)^{2},\ a\ge b>0 ⓘ
\pi = 2\,\operatorname{AGM}(1,1/\sqrt{2})^{2}\,\sum_{n=0}^{\infty}2^{n}(a_{n}^{2}-b_{n}^{2}) (Gauss–Legendre type) ⓘ
\pi = 2\,\operatorname{AGM}(1,\sqrt{1-k^{2}})\,K(k) ⓘ
hasProperty connect arithmetic means, geometric means, and elliptic integrals ⓘ
express many special values of elliptic integrals in closed form ⓘ
provide rapidly convergent algorithms for computing elliptic integrals ⓘ
provide rapidly convergent algorithms for computing pi ⓘ
historicalOrigin 19th century theory of elliptic integrals ⓘ
work of Carl Friedrich Gauss on the arithmetic–geometric mean ⓘ
relatedConcept Borwein brothers’ AGM-based pi algorithms ⓘ
Gauss transformation for elliptic integrals ⓘ
Gauss–Legendre algorithm ⓘ
Jacobi theta functions ⓘ
Landen transformations ⓘ
Ramanujan-type series for 1/\pi ⓘ
modular invariants ⓘ
relatesQuantity Gamma function at rational arguments ⓘ
arithmetic–geometric mean of two positive numbers ⓘ
complete elliptic integral K(k) ⓘ
complete elliptic integrals of the second kind ⓘ
integrals of rational functions of trigonometric functions ⓘ
modulus k of an elliptic integral ⓘ
usedFor derivation of modular equations ⓘ
evaluation of special functions ⓘ
fast algorithms for pi such as Gauss–Legendre algorithm ⓘ
high-precision computation of mathematical constants ⓘ
usesConcept Beta function ⓘ
Gamma function ⓘ
arithmetic–geometric mean ⓘ
complete elliptic integral of the first kind ⓘ
elliptic functions ⓘ
elliptic integrals ⓘ
modular functions ⓘ
pi ⓘ
theta functions ⓘ

How these facts were elicited

Referenced by (8)

Full triples — surface form annotated when it differs from this entity's canonical label.

Gauss’s constant → appearsIn → arithmetic–geometric mean identities ⓘ
Gauss’s constant → definedVia → arithmetic–geometric mean ⓘ
linked to: arithmetic–geometric mean identities
Gauss’s constant → relatedTo → Gaussian arithmetic–geometric mean ⓘ
linked to: arithmetic–geometric mean identities
arithmetic–geometric mean identities → relatedConcept → Gauss–Legendre algorithm ⓘ
linked to: arithmetic–geometric mean identities
Landen transformations → relatesTo → arithmetic–geometric mean ⓘ
linked to: arithmetic–geometric mean identities
Gauss transformation for elliptic integrals → relatedTo → arithmetic–geometric mean ⓘ
linked to: arithmetic–geometric mean identities
Gauss transformation for elliptic integrals → relatedMethod → Gauss–Legendre algorithm ⓘ
linked to: arithmetic–geometric mean identities
Gauss transformation for elliptic integrals → relatedMethod → arithmetic–geometric mean algorithm ⓘ
linked to: arithmetic–geometric mean identities