MathieuCharacteristicExponent
✖
MathieuCharacteristicExponent
gives the characteristic exponent r for Mathieu functions with characteristic value a and parameter q.
Details

- Mathematical function, suitable for both symbolic and numerical manipulation.
- All Mathieu functions have the form
where
has period
and r is the Mathieu characteristic exponent.
- For certain special arguments, MathieuCharacteristicExponent automatically evaluates to exact values.
- MathieuCharacteristicExponent can be evaluated to arbitrary numerical precision.
- MathieuCharacteristicExponent automatically threads over lists.
Examples
open allclose allBasic Examples (3)Summary of the most common use cases
Scope (15)Survey of the scope of standard use cases
Numerical Evaluation (7)

https://wolfram.com/xid/0tp309i643p23m-l274ju


https://wolfram.com/xid/0tp309i643p23m-whe1w

MathieuCharacteristicExponent threads elementwise over lists:

https://wolfram.com/xid/0tp309i643p23m-dkfve


https://wolfram.com/xid/0tp309i643p23m-b0wt9

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

https://wolfram.com/xid/0tp309i643p23m-y7k4a


https://wolfram.com/xid/0tp309i643p23m-hfml09

Evaluate efficiently at high precision:

https://wolfram.com/xid/0tp309i643p23m-di5gcr


https://wolfram.com/xid/0tp309i643p23m-bq2c6r

Compute average-case statistical intervals using Around:

https://wolfram.com/xid/0tp309i643p23m-cw18bq

Compute the elementwise values of an array:

https://wolfram.com/xid/0tp309i643p23m-thgd2

Or compute the matrix MathieuCharacteristicExponent function using MatrixFunction:

https://wolfram.com/xid/0tp309i643p23m-o5jpo

Specific Values (2)
Simple exact values are generated automatically:

https://wolfram.com/xid/0tp309i643p23m-bmqd0y

Find a value of q for which MathieuCharacteristicExponent[3,q]=1.7:

https://wolfram.com/xid/0tp309i643p23m-f2hrld


https://wolfram.com/xid/0tp309i643p23m-fo3om1

Visualization (3)
Plot the MathieuCharacteristicExponent function for integer parameters:

https://wolfram.com/xid/0tp309i643p23m-ecj8m7

Plot the MathieuCharacteristicExponent function for noninteger parameters:

https://wolfram.com/xid/0tp309i643p23m-b1j98m

Plot the real part of MathieuCharacteristicExponent:

https://wolfram.com/xid/0tp309i643p23m-cjk9wl

Plot the imaginary part of MathieuCharacteristicExponent:

https://wolfram.com/xid/0tp309i643p23m-earwdu

Function Properties (3)
MathieuCharacteristicExponent[3,x] is neither non-decreasing nor non-increasing:

https://wolfram.com/xid/0tp309i643p23m-2ra8g

MathieuCharacteristicExponent[3,x] is neither non-negative nor non-positive:

https://wolfram.com/xid/0tp309i643p23m-dvzykj

MathieuCharacteristicExponent[3,x] is neither convex nor concave:

https://wolfram.com/xid/0tp309i643p23m-l0srvu

Applications (2)Sample problems that can be solved with this function
Solve the Schrödinger equation with periodic potential:

https://wolfram.com/xid/0tp309i643p23m-c2x80s

By the Bloch theorem, solutions are bounded provided is within an energy band. The energy gap corresponds to a range of
where MathieuCharacteristicExponent has a non-vanishing imaginary part:

https://wolfram.com/xid/0tp309i643p23m-c1gowv

This shows the stability diagram for the Mathieu equation:

https://wolfram.com/xid/0tp309i643p23m-ba9xjy

Properties & Relations (2)Properties of the function, and connections to other functions
The characteristic exponent and the characteristic are inverses of each other:

https://wolfram.com/xid/0tp309i643p23m-pws0wl


https://wolfram.com/xid/0tp309i643p23m-dmcwqu

From the plot, you can see that MathieuCharacteristicExponent[x,0]=:

https://wolfram.com/xid/0tp309i643p23m-dn1iet

Wolfram Research (1996), MathieuCharacteristicExponent, Wolfram Language function, https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html.
Text
Wolfram Research (1996), MathieuCharacteristicExponent, Wolfram Language function, https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html.
Wolfram Research (1996), MathieuCharacteristicExponent, Wolfram Language function, https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html.
CMS
Wolfram Language. 1996. "MathieuCharacteristicExponent." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html.
Wolfram Language. 1996. "MathieuCharacteristicExponent." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html.
APA
Wolfram Language. (1996). MathieuCharacteristicExponent. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html
Wolfram Language. (1996). MathieuCharacteristicExponent. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html
BibTeX
@misc{reference.wolfram_2025_mathieucharacteristicexponent, author="Wolfram Research", title="{MathieuCharacteristicExponent}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html}", note=[Accessed: 29-March-2025
]}
BibLaTeX
@online{reference.wolfram_2025_mathieucharacteristicexponent, organization={Wolfram Research}, title={MathieuCharacteristicExponent}, year={1996}, url={https://reference.wolfram.com/language/ref/MathieuCharacteristicExponent.html}, note=[Accessed: 29-March-2025
]}