JacobiAmplitude
✖
JacobiAmplitude
Details

- Mathematical function, suitable for both symbolic and numerical manipulation.
- JacobiAmplitude[u,m] converts from the argument u for an elliptic function to the amplitude ϕ.
- JacobiAmplitude is the inverse of the elliptic integral of the first kind. If
, then
.
- JacobiAmplitude[u,m] has a branch cut discontinuity in the complex u plane running from
to
for every pair of integers
and
.
- For certain special arguments, JacobiAmplitude automatically evaluates to exact values.
- JacobiAmplitude can be evaluated to arbitrary numerical precision.
- JacobiAmplitude automatically threads over lists.
Examples
open allclose allBasic Examples (4)Summary of the most common use cases

https://wolfram.com/xid/0dc3l0sh425c-kzd066

Plot over a subset of the reals:

https://wolfram.com/xid/0dc3l0sh425c-wm2qg

Plot over a subset of the complexes:

https://wolfram.com/xid/0dc3l0sh425c-kiedlx

Series expansions about the origin:

https://wolfram.com/xid/0dc3l0sh425c-n1ltu7


https://wolfram.com/xid/0dc3l0sh425c-eurjnp

Scope (26)Survey of the scope of standard use cases
Numerical Evaluation (5)

https://wolfram.com/xid/0dc3l0sh425c-o5otj

The precision of the output tracks the precision of the input:

https://wolfram.com/xid/0dc3l0sh425c-gwui8b

Evaluate for complex arguments:

https://wolfram.com/xid/0dc3l0sh425c-debjig

Evaluate JacobiAmplitude efficiently at high precision:

https://wolfram.com/xid/0dc3l0sh425c-di5gcr


https://wolfram.com/xid/0dc3l0sh425c-bq2c6r

Compute average-case statistical intervals using Around:

https://wolfram.com/xid/0dc3l0sh425c-cw18bq

Compute the elementwise values of an array:

https://wolfram.com/xid/0dc3l0sh425c-thgd2

Or compute the matrix JacobiAmplitude function using MatrixFunction:

https://wolfram.com/xid/0dc3l0sh425c-o5jpo

Specific Values (4)
Simple exact values are generated automatically:

https://wolfram.com/xid/0dc3l0sh425c-dfty6e


https://wolfram.com/xid/0dc3l0sh425c-kedmi


https://wolfram.com/xid/0dc3l0sh425c-crwrl3

Values at infinity for some special cases:

https://wolfram.com/xid/0dc3l0sh425c-cw39qs


https://wolfram.com/xid/0dc3l0sh425c-f2hrld


https://wolfram.com/xid/0dc3l0sh425c-ghcykx

Parity transformation is automatically applied:

https://wolfram.com/xid/0dc3l0sh425c-hvgb9s

Visualization (3)
Plot the JacobiAmplitude functions for various values of parameter :

https://wolfram.com/xid/0dc3l0sh425c-ecj8m7

Plot JacobiAmplitude as a function of its parameter :

https://wolfram.com/xid/0dc3l0sh425c-du62z6


https://wolfram.com/xid/0dc3l0sh425c-bsucaf


https://wolfram.com/xid/0dc3l0sh425c-fpc0f

Function Properties (5)

https://wolfram.com/xid/0dc3l0sh425c-h5x4l2

It has no singularities or discontinuities:

https://wolfram.com/xid/0dc3l0sh425c-mdtl3h


https://wolfram.com/xid/0dc3l0sh425c-mn5jws


https://wolfram.com/xid/0dc3l0sh425c-poz8g


https://wolfram.com/xid/0dc3l0sh425c-ctca0g


https://wolfram.com/xid/0dc3l0sh425c-kojhy0


https://wolfram.com/xid/0dc3l0sh425c-hdm869

JacobiAmplitude is neither non-negative nor non-positive:

https://wolfram.com/xid/0dc3l0sh425c-84dui

JacobiAmplitude is neither convex nor concave:

https://wolfram.com/xid/0dc3l0sh425c-8kku21

Differentiation (3)

https://wolfram.com/xid/0dc3l0sh425c-mmas49


https://wolfram.com/xid/0dc3l0sh425c-nfbe0l


https://wolfram.com/xid/0dc3l0sh425c-fxwmfc


https://wolfram.com/xid/0dc3l0sh425c-clw10k

Series Expansions (3)

https://wolfram.com/xid/0dc3l0sh425c-ewr1h8

Plot the first three approximations for around
:

https://wolfram.com/xid/0dc3l0sh425c-binhar


https://wolfram.com/xid/0dc3l0sh425c-c7itxf

Plot the first three approximations for around
:

https://wolfram.com/xid/0dc3l0sh425c-jkkunh

JacobiAmplitude can be applied to a power series:

https://wolfram.com/xid/0dc3l0sh425c-j9mvrp


https://wolfram.com/xid/0dc3l0sh425c-bg4epz

Function Representations (3)
JacobiAmplitude is the inverse of EllipticF:

https://wolfram.com/xid/0dc3l0sh425c-cajgfk


https://wolfram.com/xid/0dc3l0sh425c-bp7jmj

TraditionalForm formatting:

https://wolfram.com/xid/0dc3l0sh425c-eu1gey

Applications (4)Sample problems that can be solved with this function
Solution of the pendulum equation in the overswing mode:

https://wolfram.com/xid/0dc3l0sh425c-izefg0
Check with the pendulum equation:

https://wolfram.com/xid/0dc3l0sh425c-c92izb


https://wolfram.com/xid/0dc3l0sh425c-bahnfv

Relativistic solution of the sine‐Gordon equation:

https://wolfram.com/xid/0dc3l0sh425c-g2iof6
Verify the solution by substituting into the sine‐Gordon equation:

https://wolfram.com/xid/0dc3l0sh425c-h9yil3

Plot the solution for different values of and
:

https://wolfram.com/xid/0dc3l0sh425c-h6ibmm


https://wolfram.com/xid/0dc3l0sh425c-jnopnz

Form and plot generalized Fourier series:

https://wolfram.com/xid/0dc3l0sh425c-p8r6y

Spherical triangle from an elliptic parameter and triple
such that
:

https://wolfram.com/xid/0dc3l0sh425c-cvpgnt

https://wolfram.com/xid/0dc3l0sh425c-c19p3g
Angles at vertices ,
and
and sides opposite to each corresponding vertex:

https://wolfram.com/xid/0dc3l0sh425c-lvlsl5

Verify Cagnoli's equation, which relates the measurements of all the angles and sides of a spherical triangle:

https://wolfram.com/xid/0dc3l0sh425c-ig9e5d

Compute the area of the triangle, also known as the spherical excess:

https://wolfram.com/xid/0dc3l0sh425c-hjye70

Compute the excess using L'Huilier's theorem [MathWorld]:

https://wolfram.com/xid/0dc3l0sh425c-dyaagc

Compute corresponding points on 3D unit sphere:

https://wolfram.com/xid/0dc3l0sh425c-ibp9i3
Check consistency between points found and spherical sides:

https://wolfram.com/xid/0dc3l0sh425c-b32d38


https://wolfram.com/xid/0dc3l0sh425c-ky6u8o

Properties & Relations (5)Properties of the function, and connections to other functions
Compose with inverse functions:

https://wolfram.com/xid/0dc3l0sh425c-emofur

Use PowerExpand to disregard the multivaluedness of the inverse function:

https://wolfram.com/xid/0dc3l0sh425c-fzgyvy

Apply trigonometric functions to JacobiAmplitude:

https://wolfram.com/xid/0dc3l0sh425c-kmykn1

Solve a transcendental equation:

https://wolfram.com/xid/0dc3l0sh425c-iy4yu

Obtain from a differential equation:

https://wolfram.com/xid/0dc3l0sh425c-ntn94

JacobiAmplitude has branch cuts from to
for any integers
and
:

https://wolfram.com/xid/0dc3l0sh425c-gap67e


https://wolfram.com/xid/0dc3l0sh425c-c8jrqk

Visualize branch cuts for different moduli:

https://wolfram.com/xid/0dc3l0sh425c-ezy01e

https://wolfram.com/xid/0dc3l0sh425c-drxec9

Possible Issues (1)Common pitfalls and unexpected behavior
The branch cuts of for
cross the real axis at
for integer
:

https://wolfram.com/xid/0dc3l0sh425c-78udx

For physical applications where a continuous version of the amplitude is desired for , use the following definition:

https://wolfram.com/xid/0dc3l0sh425c-fgte3b
The preceding function coincides with for real
and
:

https://wolfram.com/xid/0dc3l0sh425c-kpz54

Wolfram Research (1988), JacobiAmplitude, Wolfram Language function, https://reference.wolfram.com/language/ref/JacobiAmplitude.html (updated 2020).
Text
Wolfram Research (1988), JacobiAmplitude, Wolfram Language function, https://reference.wolfram.com/language/ref/JacobiAmplitude.html (updated 2020).
Wolfram Research (1988), JacobiAmplitude, Wolfram Language function, https://reference.wolfram.com/language/ref/JacobiAmplitude.html (updated 2020).
CMS
Wolfram Language. 1988. "JacobiAmplitude." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/JacobiAmplitude.html.
Wolfram Language. 1988. "JacobiAmplitude." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/JacobiAmplitude.html.
APA
Wolfram Language. (1988). JacobiAmplitude. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/JacobiAmplitude.html
Wolfram Language. (1988). JacobiAmplitude. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/JacobiAmplitude.html
BibTeX
@misc{reference.wolfram_2025_jacobiamplitude, author="Wolfram Research", title="{JacobiAmplitude}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/JacobiAmplitude.html}", note=[Accessed: 26-April-2025
]}
BibLaTeX
@online{reference.wolfram_2025_jacobiamplitude, organization={Wolfram Research}, title={JacobiAmplitude}, year={2020}, url={https://reference.wolfram.com/language/ref/JacobiAmplitude.html}, note=[Accessed: 26-April-2025
]}