# Finding the complexity of a recursive function

**URL:** <https://community.wolfram.com/t/finding-the-complexity-of-a-recursive-function/17516>\
**Category:** Questions\
**Tags:** computer-science, wolfram-alpha\
**Created:** [January 30, 2021, 6:46am UTC](https://community.wolfram.com/t/finding-the-complexity-of-a-recursive-function/17516 "2021-01-30T06:46:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![univ](https://avatars.discourse-cdn.com/v4/letter/u/9fc348/32.png) [@univ](https://community.wolfram.com/u/univ)\
**Post date:** [January 30, 2021, 6:46am UTC](https://community.wolfram.com/t/finding-the-complexity-of-a-recursive-function/17516/1 "2021-01-30T06:46:58Z")

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First time user here.

I’m trying to use Wolfram|Alpha to calculate the time complexity of a recursion function.  
When using the calculator, the results I get don’t include terms such as bigO Omega etc.

For this function:

> **[g(n)=g(n/2)+n - Wolfram|Alpha](https://www.wolframalpha.com/input/?i=g%28n%29%3Dg%28n%2F2%29%2Bn)**
>
> Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

I should get θ(n), but I can’t find it.

Your help is much appreciated.

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**Author:** ![danl](https://yyz1.discourse-cdn.com/wolfram/user_avatar/community.wolfram.com/danl/32/41267_2.png) [@danl](https://community.wolfram.com/u/danl)\
**Post date:** [January 30, 2021, 3:49pm UTC](https://community.wolfram.com/t/finding-the-complexity-of-a-recursive-function/17516/2 "2021-01-30T15:49:49Z")

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Why do you expect W|A to give a big-O form for the result? (It is not obvious to me that this shouldn’t happen, but neither is it obvious that it should.)