DiscreteLimit
DiscreteLimit[f[k],k∞]
gives the limit k∞f(k) for the sequence f[k] as k tends to infinity over the integers.
DiscreteLimit[f[k1,…,kn],{k1
,…,kn
}]
gives the nested limit
⋯
f(k1,…,kn) over the integers.
DiscreteLimit[f[k1,…,kn],{k1,…,kn}{
,…,
}]
gives the multivariate limit
f(k1,…,kn) over the integers.
Details and Options
- DiscreteLimit is also known as discrete limit or limit over the integers.
- DiscreteLimit computes the limiting value of a sequence f as its variables k or ki get arbitrarily large.
- DiscreteLimit[f,k∞] can be entered as
f. A template
can be entered as
dlim
, and
moves the cursor from the underscript to the body. - DiscreteLimit[f,{k1,…,kn}{
,…,
}] can be entered as
…
f. - The possible limit points
are ±∞. - For a finite limit value f*:
-
DiscreteLimit[f[k],k∞]f* for every
there is a
such that
implies ![TemplateBox[{{{f, (, k, )}, -, {f, ^, *}}}, Abs]<epsilon TemplateBox[{{{f, (, k, )}, -, {f, ^, *}}}, Abs]<epsilon](Files/DiscreteLimit.en/31.png)
DiscreteLimit[f[k1,…,kn],{k1,…,kn}{∞,…,∞}]f* for every
there is a
such that
implies ![TemplateBox[{{{f, (, {{k, _, 1}, ,, ..., ,, {k, _, n}}, )}, -, {f, ^, *}}}, Abs]<epsilon TemplateBox[{{{f, (, {{k, _, 1}, ,, ..., ,, {k, _, n}}, )}, -, {f, ^, *}}}, Abs]<epsilon](Files/DiscreteLimit.en/35.png)
- DiscreteLimit[f[k],k-∞] is equivalent to DiscreteLimit[f[-l],l∞] etc.
- DiscreteLimit returns Indeterminate when it can prove that the limit does not exist, and returns unevaluated when no limit can be found.
- The following options can be given:
-
Assumptions $Assumptions assumptions on parameters GenerateConditions Automatic whether to generate conditions on parameters Method Automatic method to use PerformanceGoal "Quality" aspects of performance to optimize - 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, DiscreteLimit typically solves more problems or produces simpler results, but it potentially uses more time and memory.
Examples
open allclose allBasic Examples (4)
Plot the sequence and its limit:
Limit of a multivariate sequence:
Plot the sequence and its limit:
Use
dlim
to enter the template
and
to move from the underscript to the body:
TraditionalForm typesetting:
Scope (37)
Options (6)
Applications (35)
Properties & Relations (15)
Neat Examples (1)
See Also
Limit DiscreteMaxLimit DiscreteMinLimit SumConvergence RSolveValue
Related Guides
Introduced in 2017
(11.2)