BesselY
✖
BesselY
Details

- Mathematical function, suitable for both symbolic and numerical manipulation.
satisfies the differential equation
.
- BesselY[n,z] has a branch cut discontinuity in the complex z plane running from
to
.
- FullSimplify and FunctionExpand include transformation rules for BesselY.
- For certain special arguments, BesselY automatically evaluates to exact values.
- BesselY can be evaluated to arbitrary numerical precision.
- BesselY automatically threads over lists.
- BesselY can be used with Interval and CenteredInterval objects. »
Examples
open allclose allBasic Examples (5)Summary of the most common use cases

https://wolfram.com/xid/0e7q3buv-ljxi3b

Plot over a subset of the reals:

https://wolfram.com/xid/0e7q3buv-e5lx5h

Plot over a subset of the complexes:

https://wolfram.com/xid/0e7q3buv-kiedlx

Series expansion at the origin:

https://wolfram.com/xid/0e7q3buv-d4yi7q

Series expansion at Infinity:

https://wolfram.com/xid/0e7q3buv-l1rgih

Scope (44)Survey of the scope of standard use cases
Numerical Evaluation (6)

https://wolfram.com/xid/0e7q3buv-l274ju


https://wolfram.com/xid/0e7q3buv-b5f0h8

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

https://wolfram.com/xid/0e7q3buv-d0j3k

Evaluate for complex arguments and parameters:

https://wolfram.com/xid/0e7q3buv-crl1d1

Evaluate BesselY efficiently at high precision:

https://wolfram.com/xid/0e7q3buv-di5gcr


https://wolfram.com/xid/0e7q3buv-bq2c6r

Compute worst-case guaranteed intervals using Interval and CenteredInterval objects:

https://wolfram.com/xid/0e7q3buv-e6w1am


https://wolfram.com/xid/0e7q3buv-lmyeh7

Or compute average-case statistical intervals using Around:

https://wolfram.com/xid/0e7q3buv-cw18bq

Compute the elementwise values of an array:

https://wolfram.com/xid/0e7q3buv-thgd2

Or compute the matrix BesselY function using MatrixFunction:

https://wolfram.com/xid/0e7q3buv-o5jpo

Specific Values (4)
Value of BesselY for integers () orders at
:

https://wolfram.com/xid/0e7q3buv-nww7l

For half-integer indices, BesselY evaluates to elementary functions:

https://wolfram.com/xid/0e7q3buv-s0gpv


https://wolfram.com/xid/0e7q3buv-bdij6w


https://wolfram.com/xid/0e7q3buv-l6bi6x

Find the first zero of using Solve:

https://wolfram.com/xid/0e7q3buv-otdu3


https://wolfram.com/xid/0e7q3buv-b4co4x

Visualization (3)
Plot the BesselY function for integer orders ():

https://wolfram.com/xid/0e7q3buv-ecj8m7

Plot the real and imaginary parts of the BesselY function for integer orders ():

https://wolfram.com/xid/0e7q3buv-gsa4di


https://wolfram.com/xid/0e7q3buv-f8bg51


https://wolfram.com/xid/0e7q3buv-i11ev

Function Properties (10)
is defined for all real values greater than 0:

https://wolfram.com/xid/0e7q3buv-cl7ele


https://wolfram.com/xid/0e7q3buv-de3irc

Approximate function range of :

https://wolfram.com/xid/0e7q3buv-evf2yr

Approximate function range of :

https://wolfram.com/xid/0e7q3buv-fphbrc


https://wolfram.com/xid/0e7q3buv-1lxpj

BesselY is neither non-decreasing nor non-increasing:

https://wolfram.com/xid/0e7q3buv-rmb7f


https://wolfram.com/xid/0e7q3buv-dm9qzk

BesselY is not injective:

https://wolfram.com/xid/0e7q3buv-fxi9f9


https://wolfram.com/xid/0e7q3buv-9v5fk


https://wolfram.com/xid/0e7q3buv-zf7zy

BesselY is not surjective:

https://wolfram.com/xid/0e7q3buv-gex1hh


https://wolfram.com/xid/0e7q3buv-gchn40


https://wolfram.com/xid/0e7q3buv-q6hnks

BesselY is neither non-negative nor non-positive:

https://wolfram.com/xid/0e7q3buv-fxktl8

has both singularity and discontinuity for z≤0:

https://wolfram.com/xid/0e7q3buv-ho029y


https://wolfram.com/xid/0e7q3buv-8fm1oa

BesselY is neither convex nor concave:

https://wolfram.com/xid/0e7q3buv-duxck

TraditionalForm formatting:

https://wolfram.com/xid/0e7q3buv-fu7s

Differentiation (3)

https://wolfram.com/xid/0e7q3buv-mmas49


https://wolfram.com/xid/0e7q3buv-nfbe0l


https://wolfram.com/xid/0e7q3buv-fxwmfc


https://wolfram.com/xid/0e7q3buv-odmgl1

Integration (3)
Indefinite integral of BesselY:

https://wolfram.com/xid/0e7q3buv-bponid

Integrate expressions involving BesselY:

https://wolfram.com/xid/0e7q3buv-yf3x2


https://wolfram.com/xid/0e7q3buv-euonzf

Definite integral of BesselY over its real domain:

https://wolfram.com/xid/0e7q3buv-ea53fk

Series Expansions (5)

https://wolfram.com/xid/0e7q3buv-ewr1h8

Plot the first three approximations for around
:

https://wolfram.com/xid/0e7q3buv-binhar

General term in the series expansion of BesselY:

https://wolfram.com/xid/0e7q3buv-haee98

Asymptotic approximation of BesselY:

https://wolfram.com/xid/0e7q3buv-dlm2b6

Taylor expansion at a generic point:

https://wolfram.com/xid/0e7q3buv-jwxla7

BesselY can be applied to a power series:

https://wolfram.com/xid/0e7q3buv-fy8x4e

Integral Transforms (3)
Compute the Laplace transform using LaplaceTransform:

https://wolfram.com/xid/0e7q3buv-eqbky1


https://wolfram.com/xid/0e7q3buv-6lmz2g


https://wolfram.com/xid/0e7q3buv-7mn4u

Function Identities and Simplifications (3)
Use FullSimplify to simplify Bessel functions:

https://wolfram.com/xid/0e7q3buv-c0lab5


https://wolfram.com/xid/0e7q3buv-cpyrfv

For integer and arbitrary fixed
,
:

https://wolfram.com/xid/0e7q3buv-er2560

Function Representations (4)
Integral representation of BesselY:

https://wolfram.com/xid/0e7q3buv-yvgyb

Represent using BesselJ and Sin for non-integer :

https://wolfram.com/xid/0e7q3buv-d8ooz4

BesselY can be represented in terms of MeijerG:

https://wolfram.com/xid/0e7q3buv-l6ctqg


https://wolfram.com/xid/0e7q3buv-blwjy6

BesselY can be represented as a DifferenceRoot:

https://wolfram.com/xid/0e7q3buv-jkfrf

Applications (2)Sample problems that can be solved with this function
Solve the Bessel differential equation:

https://wolfram.com/xid/0e7q3buv-glyrou

Solve a differential equation:

https://wolfram.com/xid/0e7q3buv-i6qtk0

Solve the inhomogeneous Bessel differential equation:

https://wolfram.com/xid/0e7q3buv-jvq87f

Properties & Relations (3)Properties of the function, and connections to other functions
Use FullSimplify to simplify Bessel functions:

https://wolfram.com/xid/0e7q3buv-jbuxy

BesselY can be represented as a DifferentialRoot:

https://wolfram.com/xid/0e7q3buv-f83v5n

The exponential generating function for BesselY:

https://wolfram.com/xid/0e7q3buv-gaiyeu

Possible Issues (1)Common pitfalls and unexpected behavior
With numeric arguments, half-integer Bessel functions are not automatically evaluated:

https://wolfram.com/xid/0e7q3buv-e8j10a

For symbolic arguments they are:

https://wolfram.com/xid/0e7q3buv-dlr12e

This can lead to major inaccuracies in machine-precision evaluation:

https://wolfram.com/xid/0e7q3buv-i33017

Wolfram Research (1988), BesselY, Wolfram Language function, https://reference.wolfram.com/language/ref/BesselY.html (updated 2022).
Text
Wolfram Research (1988), BesselY, Wolfram Language function, https://reference.wolfram.com/language/ref/BesselY.html (updated 2022).
Wolfram Research (1988), BesselY, Wolfram Language function, https://reference.wolfram.com/language/ref/BesselY.html (updated 2022).
CMS
Wolfram Language. 1988. "BesselY." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/BesselY.html.
Wolfram Language. 1988. "BesselY." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/BesselY.html.
APA
Wolfram Language. (1988). BesselY. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BesselY.html
Wolfram Language. (1988). BesselY. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BesselY.html
BibTeX
@misc{reference.wolfram_2025_bessely, author="Wolfram Research", title="{BesselY}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/BesselY.html}", note=[Accessed: 01-June-2025
]}
BibLaTeX
@online{reference.wolfram_2025_bessely, organization={Wolfram Research}, title={BesselY}, year={2022}, url={https://reference.wolfram.com/language/ref/BesselY.html}, note=[Accessed: 01-June-2025
]}