AsymptoticEqual
✖
AsymptoticEqual
Details and Options




- Asymptotic equal is also expressed as f is big-theta of g, f is bounded by g, f is of order g, and f grows as g. The point x* is often assumed from context.
- Asymptotic equal is an equivalence relation and means
when x is near x* for some constants
and
. It is a coarser asymptotic equivalence relation than AsymptoticEquivalent.
- Typical uses include expressing simple bounds for functions and sequences near some point. It is frequently used for asymptotic solutions to equations and to give simple lower bounds for computational complexity.
- For a finite limit point x* and {
,…,
}, the result is:
-
AsymptoticEqual[f[x],g[x],xx*] there exist ,
and
such that
implies
AsymptoticEqual[f[x1,…,xn],g[x1,…,xn],{x1,…,xn}{ ,…,
}]
there exist ,
and
such that
implies
- For an infinite limit point, the result is:
-
AsymptoticEqual[f[x],g[x],x∞] there exist ,
and
such that
implies
AsymptoticEqual[f[x1,…,xn],g[x1,…,xn],{x1,…,xn}{∞,…,∞}] there exist ,
and
such that
implies
- AsymptoticEqual[f[x],g[x],xx*] exists if and only if MinLimit[Abs[f[x]/g[x]],xx*]>0 and MaxLimit[Abs[f[x]/g[x]],xx*]<∞ when g[x] does not have an infinite set of zeros near x*.
- The following options can be given:
-
Assumptions $Assumptions assumptions on parameters Direction Reals direction to approach the limit point GenerateConditions Automatic generate conditions for parameters Method Automatic method to use PerformanceGoal "Quality" what to optimize - Possible settings for Direction include:
-
Reals or "TwoSided" from both real directions "FromAbove" or -1 from above or larger values "FromBelow" or +1 from below or smaller values Complexes from all complex directions Exp[ θ] in the direction {dir1,…,dirn} use direction diri for variable xi independently - DirectionExp[ θ] at x* indicates the direction tangent of a curve approaching the limit point x*.
- Possible settings for GenerateConditions include:
-
Automatic non-generic conditions only True all conditions False no conditions None return unevaluated if conditions are needed - Possible settings for PerformanceGoal include $PerformanceGoal, "Quality" and "Speed". With the "Quality" setting, Limit typically solves more problems or produces simpler results, but it potentially uses more time and memory.



Examples
open allclose allBasic Examples (2)Summary of the most common use cases

https://wolfram.com/xid/01lrfsocn65rcn8re-fd2m9a

The former can be "sandwiched" between two constant multiples of the latter:

https://wolfram.com/xid/01lrfsocn65rcn8re-ekzxa6


https://wolfram.com/xid/01lrfsocn65rcn8re-pwvtd

The former can be "sandwiched" between two constant multiples of the latter:

https://wolfram.com/xid/01lrfsocn65rcn8re-bah9

Scope (9)Survey of the scope of standard use cases
Compare functions that are not strictly positive:

https://wolfram.com/xid/01lrfsocn65rcn8re-jc83n1

Show that diverges at the same rate as
at the origin:

https://wolfram.com/xid/01lrfsocn65rcn8re-nnsqde

Answers may be Boolean expressions rather than explicit True or False:

https://wolfram.com/xid/01lrfsocn65rcn8re-sxh24

When comparing functions with parameters, conditions for the result may be generated:

https://wolfram.com/xid/01lrfsocn65rcn8re-w0qbz9

By default, a two-sided comparison of the functions is made:

https://wolfram.com/xid/01lrfsocn65rcn8re-gclur

When comparing larger values of ,
vanishes at the same rate as
:

https://wolfram.com/xid/01lrfsocn65rcn8re-szc5cz

The relationship fails for smaller values of :

https://wolfram.com/xid/01lrfsocn65rcn8re-d90890

Visualize the ratio of the two functions, showing it approaches a nonzero limit from above:

https://wolfram.com/xid/01lrfsocn65rcn8re-2mykrk

Functions like Sqrt may have the same relationship in both real directions along the negative reals:

https://wolfram.com/xid/01lrfsocn65rcn8re-pgmwgz

If approached from above in the complex plane, the same relationship is observed:

https://wolfram.com/xid/01lrfsocn65rcn8re-eh3ic2

However, approaching from below in the complex plane produces a different result:

https://wolfram.com/xid/01lrfsocn65rcn8re-7oj7pv

This is due to a branch cut where the imaginary part of Sqrt reverses sign as the axis is crossed:

https://wolfram.com/xid/01lrfsocn65rcn8re-xj6jic

Hence, the relationship does not hold in the complex plane in general:

https://wolfram.com/xid/01lrfsocn65rcn8re-9gewpp

Visualize the relative sizes of the functions when approached from the four real and imaginary directions:

https://wolfram.com/xid/01lrfsocn65rcn8re-ejoqih

Compare multivariate functions:

https://wolfram.com/xid/01lrfsocn65rcn8re-485nrb

Visualize the norms of the two functions:

https://wolfram.com/xid/01lrfsocn65rcn8re-w2pict

Compare multivariate functions at infinity:

https://wolfram.com/xid/01lrfsocn65rcn8re-2pjlet

Use parameters when comparing multivariate functions:

https://wolfram.com/xid/01lrfsocn65rcn8re-jkkb89

Options (9)Common values & functionality for each option
Assumptions (1)
Specify conditions on parameters using Assumptions:

https://wolfram.com/xid/01lrfsocn65rcn8re-bsi62b

Different assumptions can produce different results:

https://wolfram.com/xid/01lrfsocn65rcn8re-9nq9mt

Direction (5)

https://wolfram.com/xid/01lrfsocn65rcn8re-wh362x


https://wolfram.com/xid/01lrfsocn65rcn8re-47rpfm


https://wolfram.com/xid/01lrfsocn65rcn8re-ieye3l


https://wolfram.com/xid/01lrfsocn65rcn8re-7b33iw

Equality at piecewise discontinuities:

https://wolfram.com/xid/01lrfsocn65rcn8re-dtc1xq


https://wolfram.com/xid/01lrfsocn65rcn8re-1s90kg

Since it fails in one direction, the two-sided result is false as well:

https://wolfram.com/xid/01lrfsocn65rcn8re-ce2ne8

Visualize the two functions and their ratio:

https://wolfram.com/xid/01lrfsocn65rcn8re-fpzs

Equality at a pole is independent of the direction of approach:

https://wolfram.com/xid/01lrfsocn65rcn8re-o19pbz


https://wolfram.com/xid/01lrfsocn65rcn8re-4oak0w


https://wolfram.com/xid/01lrfsocn65rcn8re-6gbhpd


https://wolfram.com/xid/01lrfsocn65rcn8re-7wy1b3


https://wolfram.com/xid/01lrfsocn65rcn8re-bsn6zf


https://wolfram.com/xid/01lrfsocn65rcn8re-2fd8pf


https://wolfram.com/xid/01lrfsocn65rcn8re-7508fb


https://wolfram.com/xid/01lrfsocn65rcn8re-iio0jj

Compute equality, approaching from different quadrants:

https://wolfram.com/xid/01lrfsocn65rcn8re-xstf5t

https://wolfram.com/xid/01lrfsocn65rcn8re-n5ghf
Approaching the origin from the third quadrant:

https://wolfram.com/xid/01lrfsocn65rcn8re-5ei7y4


https://wolfram.com/xid/01lrfsocn65rcn8re-0n4vor

Approaching the origin from the second quadrant:

https://wolfram.com/xid/01lrfsocn65rcn8re-772jnn

Approaching the origin from the right half-plane:

https://wolfram.com/xid/01lrfsocn65rcn8re-pa15d2

Approaching the origin from the bottom half-plane:

https://wolfram.com/xid/01lrfsocn65rcn8re-46gbl5

Visualize the ratio of the functions:

https://wolfram.com/xid/01lrfsocn65rcn8re-ry52i7

GenerateConditions (3)
Return a result without stating conditions:

https://wolfram.com/xid/01lrfsocn65rcn8re-6rd3fa

This result is only valid if n>0:

https://wolfram.com/xid/01lrfsocn65rcn8re-uhf4he


https://wolfram.com/xid/01lrfsocn65rcn8re-1er301

Return unevaluated if the results depend on the value of parameters:

https://wolfram.com/xid/01lrfsocn65rcn8re-2lepxp


https://wolfram.com/xid/01lrfsocn65rcn8re-1s089w

By default, conditions are not generated if only special values invalidate the result:

https://wolfram.com/xid/01lrfsocn65rcn8re-tdcquw

With GenerateConditions->True, even these non-generic conditions are reported:

https://wolfram.com/xid/01lrfsocn65rcn8re-291b1m

Applications (10)Sample problems that can be solved with this function
Basic Applications (5)
Show that two monomials equivalent at infinity have the same power:

https://wolfram.com/xid/01lrfsocn65rcn8re-xlwmnq


https://wolfram.com/xid/01lrfsocn65rcn8re-3gga8g

Use this to show that two polynomials that are equivalent are of the same order:

https://wolfram.com/xid/01lrfsocn65rcn8re-v7sj5o

Visualize the ratios of three pairs of asymptotically equivalent polynomials:

https://wolfram.com/xid/01lrfsocn65rcn8re-0o3ud1

Show that two monomials in equivalent at
have the same power:

https://wolfram.com/xid/01lrfsocn65rcn8re-49j3mw


https://wolfram.com/xid/01lrfsocn65rcn8re-hognh6

Use this to show that two polynomials in that are equivalent have the same leading monomial:

https://wolfram.com/xid/01lrfsocn65rcn8re-33ul3n

Visualize the ratios of three pairs of asymptotically equivalent polynomials in :

https://wolfram.com/xid/01lrfsocn65rcn8re-f412xf


https://wolfram.com/xid/01lrfsocn65rcn8re-kmoq7r


https://wolfram.com/xid/01lrfsocn65rcn8re-yt01k0

Even though the absolute value of their ratio wiggles incessantly as , it is bounded away from
:

https://wolfram.com/xid/01lrfsocn65rcn8re-l8frvd


https://wolfram.com/xid/01lrfsocn65rcn8re-ddqabt

Even though the absolute value of their ratio wiggles incessantly as , it is bounded away from
:

https://wolfram.com/xid/01lrfsocn65rcn8re-x99r0n


https://wolfram.com/xid/01lrfsocn65rcn8re-8oriwy


https://wolfram.com/xid/01lrfsocn65rcn8re-w7jyr7

Computational Complexity (3)
In a bubble sort, adjoining neighbors are compared and swapped if they are out of order. After one pass of n-1 comparisons, the largest element is at the end. The process is then repeated on remaining n-1 elements, and so forth, until only two elements at the very beginning remain. If comparison and swap takes c steps, the total number of steps for the sort is as follows:

https://wolfram.com/xid/01lrfsocn65rcn8re-g63m1r

Show that , and thus the algorithm has quadratic run time:

https://wolfram.com/xid/01lrfsocn65rcn8re-8x1qob

Visualize the ratios for the two functions for different values of c:

https://wolfram.com/xid/01lrfsocn65rcn8re-lwgbuf

In a merge sort, the list of elements is split in two, each half is sorted, and then the two halves are combined. Thus, the time T[n] to do the sort will be the sum of some constant time b to compute the middle, 2T[n/2] to sort each half, and some multiple a n of the number of elements to combine the two halves:

https://wolfram.com/xid/01lrfsocn65rcn8re-hgn32u

Solve the recurrence equation to find the time t to sort n elements:

https://wolfram.com/xid/01lrfsocn65rcn8re-nn6dxo

Show that , and thus the algorithm has
run time:

https://wolfram.com/xid/01lrfsocn65rcn8re-u1dsrr

Strassen's algorithm was the first subcubic matrix multiplication algorithm found. It consists of four steps: splitting each of the two matrices into 4 equal-sized submatrices, forming 14 particular linear combinations out of the 8 submatrices, multiplying 7 pairs of these and forming linear combinations of the 7 results. The time
to do the multiplication will therefore be a constant time
to split the matrix,
for forming linear combinations in the second and fourth steps and
for the third step:

https://wolfram.com/xid/01lrfsocn65rcn8re-okd8ll

Solve the recurrence relation:

https://wolfram.com/xid/01lrfsocn65rcn8re-qbdv82

Though the result is complicated, it is asymptotically equal to :

https://wolfram.com/xid/01lrfsocn65rcn8re-xadpzc

Compare the rate of growth of the naive cubic algorithm and Strassen's algorithm:

https://wolfram.com/xid/01lrfsocn65rcn8re-o4nj4q

Convergence Testing (2)
A sequence is said to be absolutely summable if
. If a second sequence
, the comparison test states that
is absolutely summable if and only if
is. Use the test to show that
converges by comparing with the sum of
:

https://wolfram.com/xid/01lrfsocn65rcn8re-c6ak1d


https://wolfram.com/xid/01lrfsocn65rcn8re-focct0

Compare with the answer given by SumConvergence:

https://wolfram.com/xid/01lrfsocn65rcn8re-n3mdiq

Show that convergence by comparing with the sum of
:

https://wolfram.com/xid/01lrfsocn65rcn8re-5fvg9h


https://wolfram.com/xid/01lrfsocn65rcn8re-732a8a

Show that divergence by comparing with the sum of
:

https://wolfram.com/xid/01lrfsocn65rcn8re-tg0kcf


https://wolfram.com/xid/01lrfsocn65rcn8re-y36z5o

Compare with the answer given by SumConvergence:

https://wolfram.com/xid/01lrfsocn65rcn8re-6xnxna

The sequence , and thus is not absolutely summable:

https://wolfram.com/xid/01lrfsocn65rcn8re-sea9r4


https://wolfram.com/xid/01lrfsocn65rcn8re-6gu07k

A function is said to be absolutely integrable on
if
. If
and
are continuous on the open interval
and
at both
and
, the comparison test states that
is absolutely integrable if and only if
is. Use the test to show that
is absolutely integrable on
:

https://wolfram.com/xid/01lrfsocn65rcn8re-jqu98u


https://wolfram.com/xid/01lrfsocn65rcn8re-0mll1r

Since is integrable on
, so is
:

https://wolfram.com/xid/01lrfsocn65rcn8re-rvsvtz

That is not integrable over
can be shown by comparing it with
:

https://wolfram.com/xid/01lrfsocn65rcn8re-sak382


https://wolfram.com/xid/01lrfsocn65rcn8re-n1as9a

The result follows from the nonintegrability of on the unit interval:

https://wolfram.com/xid/01lrfsocn65rcn8re-cosev6


The function is not absolutely integrable on
:

https://wolfram.com/xid/01lrfsocn65rcn8re-v7866i


Show that is not absolutely integrable either, by comparing it to
:

https://wolfram.com/xid/01lrfsocn65rcn8re-2hi0mp


https://wolfram.com/xid/01lrfsocn65rcn8re-ti2r3w

Properties & Relations (6)Properties of the function, and connections to other functions
AsymptoticEqual is an equivalence relation, meaning it is reflexive ():

https://wolfram.com/xid/01lrfsocn65rcn8re-djhovi

It is transitive ( and
implies
):

https://wolfram.com/xid/01lrfsocn65rcn8re-iflbs4

https://wolfram.com/xid/01lrfsocn65rcn8re-jo9vs

And it is symmetric ( implies
):

https://wolfram.com/xid/01lrfsocn65rcn8re-2nf1s

AsymptoticEqual[f[x],g[x],xx0] iff MaxLimit[Abs[f[x]/g[x]],xx0]<∞ and MinLimit[Abs[f[x]/g[x]],xx0]>0:

https://wolfram.com/xid/01lrfsocn65rcn8re-jjmtdb

https://wolfram.com/xid/01lrfsocn65rcn8re-bwsd3m


https://wolfram.com/xid/01lrfsocn65rcn8re-jqjzfw

https://wolfram.com/xid/01lrfsocn65rcn8re-fdt3ec

AsymptoticEqual[f[x],g[x],xx0] if 0<Limit[Abs[f[x]/g[x]],xx0]<∞:

https://wolfram.com/xid/01lrfsocn65rcn8re-d20hmb

https://wolfram.com/xid/01lrfsocn65rcn8re-jy4cm4

However, the limit need not exist:

https://wolfram.com/xid/01lrfsocn65rcn8re-5766nc

https://wolfram.com/xid/01lrfsocn65rcn8re-79sson


https://wolfram.com/xid/01lrfsocn65rcn8re-f0y2os

https://wolfram.com/xid/01lrfsocn65rcn8re-y915f


https://wolfram.com/xid/01lrfsocn65rcn8re-z10kcc

https://wolfram.com/xid/01lrfsocn65rcn8re-jnddz8


https://wolfram.com/xid/01lrfsocn65rcn8re-3jo0a6

The converse, however, is false:

https://wolfram.com/xid/01lrfsocn65rcn8re-h1p3hx

https://wolfram.com/xid/01lrfsocn65rcn8re-441xqo


https://wolfram.com/xid/01lrfsocn65rcn8re-fhpchq

https://wolfram.com/xid/01lrfsocn65rcn8re-bgd4x

The converse is false, so AsymptoticEqual is coarser than AsymptoticEquivalent:

https://wolfram.com/xid/01lrfsocn65rcn8re-m24dj

https://wolfram.com/xid/01lrfsocn65rcn8re-ckmxl0

Wolfram Research (2018), AsymptoticEqual, Wolfram Language function, https://reference.wolfram.com/language/ref/AsymptoticEqual.html.
Text
Wolfram Research (2018), AsymptoticEqual, Wolfram Language function, https://reference.wolfram.com/language/ref/AsymptoticEqual.html.
Wolfram Research (2018), AsymptoticEqual, Wolfram Language function, https://reference.wolfram.com/language/ref/AsymptoticEqual.html.
CMS
Wolfram Language. 2018. "AsymptoticEqual." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/AsymptoticEqual.html.
Wolfram Language. 2018. "AsymptoticEqual." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/AsymptoticEqual.html.
APA
Wolfram Language. (2018). AsymptoticEqual. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AsymptoticEqual.html
Wolfram Language. (2018). AsymptoticEqual. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AsymptoticEqual.html
BibTeX
@misc{reference.wolfram_2025_asymptoticequal, author="Wolfram Research", title="{AsymptoticEqual}", year="2018", howpublished="\url{https://reference.wolfram.com/language/ref/AsymptoticEqual.html}", note=[Accessed: 23-April-2025
]}
BibLaTeX
@online{reference.wolfram_2025_asymptoticequal, organization={Wolfram Research}, title={AsymptoticEqual}, year={2018}, url={https://reference.wolfram.com/language/ref/AsymptoticEqual.html}, note=[Accessed: 23-April-2025
]}