Is there such a thing in math the inverse of a sequence?Is the sequence $u_n=sum_p=0^n(arctanfracx2^p)^2$ convergent?Does there exist a convergent sequence $a_n$ such that $n d(a_n+1,a_n)$ is not bounded?Show that the sequence $left(frac2^nn!right)$ has a limit.Which is the function that this sequence of functions convergesA convergent / divergent sequence of positive numbers such that $lim fracs_n+1s_n=1$Proof that every bounded sequence in the real numbers has a convergent subsequenceSuch thing as inverse/undo “search” or “filter” operatorConfusion arising from the 'infiniteness' of a sequence.Every sequence of the real numbers has a monotone subsequence.Showing the difference of an unbounded sequence and a convergent sequence is unbounded

black dwarf stars and dark matter

How is it possible for user's password to be changed after storage was encrypted? (on OS X, Android)

The magic money tree problem

Why is "Reports" in sentence down without "The"

What Brexit solution does the DUP want?

Japan - Plan around max visa duration

Why is this code 6.5x slower with optimizations enabled?

Can a German sentence have two subjects?

A newer friend of my brother's gave him a load of baseball cards that are supposedly extremely valuable. Is this a scam?

How does one intimidate enemies without having the capacity for violence?

Possibly bubble sort algorithm

How long does it take to type this?

Why CLRS example on residual networks does not follows its formula?

Can an x86 CPU running in real mode be considered to be basically an 8086 CPU?

Can I interfere when another PC is about to be attacked?

How is the claim "I am in New York only if I am in America" the same as "If I am in New York, then I am in America?

"You are your self first supporter", a more proper way to say it

Why Is Death Allowed In the Matrix?

Why don't electron-positron collisions release infinite energy?

How to report a triplet of septets in NMR tabulation?

DOS, create pipe for stdin/stdout of command.com(or 4dos.com) in C or Batch?

Is it possible to do 50 km distance without any previous training?

Infinite past with a beginning?

If Manufacturer spice model and Datasheet give different values which should I use?



Is there such a thing in math the inverse of a sequence?


Is the sequence $u_n=sum_p=0^n(arctanfracx2^p)^2$ convergent?Does there exist a convergent sequence $a_n$ such that $n d(a_n+1,a_n)$ is not bounded?Show that the sequence $left(frac2^nn!right)$ has a limit.Which is the function that this sequence of functions convergesA convergent / divergent sequence of positive numbers such that $lim fracs_n+1s_n=1$Proof that every bounded sequence in the real numbers has a convergent subsequenceSuch thing as inverse/undo “search” or “filter” operatorConfusion arising from the 'infiniteness' of a sequence.Every sequence of the real numbers has a monotone subsequence.Showing the difference of an unbounded sequence and a convergent sequence is unbounded













1












$begingroup$


Such as can I construct a sequence by reversing the order of the approximating sequence of $frac13$? So such inverse would look like $left….,0.333333333,0.3333333,0.333333,...0.3right$.



I had this question when I was constructing a sequence that is bounded between 0 and 1/2 and not convergent to 0 for a homework question.










share|cite|improve this question











$endgroup$











  • $begingroup$
    You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
    $endgroup$
    – kingW3
    Mar 8 at 1:50






  • 1




    $begingroup$
    And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
    $endgroup$
    – астон вілла олоф мэллбэрг
    Mar 8 at 3:44











  • $begingroup$
    This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
    $endgroup$
    – Somos
    Mar 8 at 5:45
















1












$begingroup$


Such as can I construct a sequence by reversing the order of the approximating sequence of $frac13$? So such inverse would look like $left….,0.333333333,0.3333333,0.333333,...0.3right$.



I had this question when I was constructing a sequence that is bounded between 0 and 1/2 and not convergent to 0 for a homework question.










share|cite|improve this question











$endgroup$











  • $begingroup$
    You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
    $endgroup$
    – kingW3
    Mar 8 at 1:50






  • 1




    $begingroup$
    And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
    $endgroup$
    – астон вілла олоф мэллбэрг
    Mar 8 at 3:44











  • $begingroup$
    This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
    $endgroup$
    – Somos
    Mar 8 at 5:45














1












1








1





$begingroup$


Such as can I construct a sequence by reversing the order of the approximating sequence of $frac13$? So such inverse would look like $left….,0.333333333,0.3333333,0.333333,...0.3right$.



I had this question when I was constructing a sequence that is bounded between 0 and 1/2 and not convergent to 0 for a homework question.










share|cite|improve this question











$endgroup$




Such as can I construct a sequence by reversing the order of the approximating sequence of $frac13$? So such inverse would look like $left….,0.333333333,0.3333333,0.333333,...0.3right$.



I had this question when I was constructing a sequence that is bounded between 0 and 1/2 and not convergent to 0 for a homework question.







real-analysis sequences-and-series inverse






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Mar 8 at 5:47







user917099

















asked Mar 8 at 1:40









user917099user917099

1616




1616











  • $begingroup$
    You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
    $endgroup$
    – kingW3
    Mar 8 at 1:50






  • 1




    $begingroup$
    And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
    $endgroup$
    – астон вілла олоф мэллбэрг
    Mar 8 at 3:44











  • $begingroup$
    This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
    $endgroup$
    – Somos
    Mar 8 at 5:45

















  • $begingroup$
    You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
    $endgroup$
    – kingW3
    Mar 8 at 1:50






  • 1




    $begingroup$
    And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
    $endgroup$
    – астон вілла олоф мэллбэрг
    Mar 8 at 3:44











  • $begingroup$
    This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
    $endgroup$
    – Somos
    Mar 8 at 5:45
















$begingroup$
You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
$endgroup$
– kingW3
Mar 8 at 1:50




$begingroup$
You can't, imagine if the first element has $n$ three's but in the original sequence the element with $n+1$ three's come after the one with $n$ three's hence in the new sequence it should be before the first element, a contradiction.
$endgroup$
– kingW3
Mar 8 at 1:50




1




1




$begingroup$
And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
$endgroup$
– астон вілла олоф мэллбэрг
Mar 8 at 3:44





$begingroup$
And no, there is a difference between stupid and bad questions, in your case the votes have matchedvso your question divides opinion. Giving enough context helps when you are asking a "stupid" question, i.e. mentioning that you heard it in class or in conversation with a friend or online on some webpage helps. Also mention what was the broad topic if the conversation, so that others will be able to address concerns relating to that in the answer as well.
$endgroup$
– астон вілла олоф мэллбэрг
Mar 8 at 3:44













$begingroup$
This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
$endgroup$
– Somos
Mar 8 at 5:45





$begingroup$
This is a good question. In several cases, a sequence makes sense for negative values of the index. For example, the Fibonacci numbers $0,1,1,2,3,5,dots$ can be exteneded to negative indices as $dots,5,-3,2,-1,1$. I encounter this kind of thing in the OEIS many time.
$endgroup$
– Somos
Mar 8 at 5:45











1 Answer
1






active

oldest

votes


















9












$begingroup$

A sequence is ultimately a map whose domain is $mathbb N$, but the object that you describe (a) has no first term, and (b) terminates.



If you want, I suppose you could define an object whose indices run from $-infty$ to $0$, but that's not appreciably different from looking at the original sequence while standing on your head.






share|cite|improve this answer











$endgroup$













    Your Answer





    StackExchange.ifUsing("editor", function ()
    return StackExchange.using("mathjaxEditing", function ()
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    );
    );
    , "mathjax-editing");

    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "69"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader:
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    ,
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );













    draft saved

    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3139613%2fis-there-such-a-thing-in-math-the-inverse-of-a-sequence%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    9












    $begingroup$

    A sequence is ultimately a map whose domain is $mathbb N$, but the object that you describe (a) has no first term, and (b) terminates.



    If you want, I suppose you could define an object whose indices run from $-infty$ to $0$, but that's not appreciably different from looking at the original sequence while standing on your head.






    share|cite|improve this answer











    $endgroup$

















      9












      $begingroup$

      A sequence is ultimately a map whose domain is $mathbb N$, but the object that you describe (a) has no first term, and (b) terminates.



      If you want, I suppose you could define an object whose indices run from $-infty$ to $0$, but that's not appreciably different from looking at the original sequence while standing on your head.






      share|cite|improve this answer











      $endgroup$















        9












        9








        9





        $begingroup$

        A sequence is ultimately a map whose domain is $mathbb N$, but the object that you describe (a) has no first term, and (b) terminates.



        If you want, I suppose you could define an object whose indices run from $-infty$ to $0$, but that's not appreciably different from looking at the original sequence while standing on your head.






        share|cite|improve this answer











        $endgroup$



        A sequence is ultimately a map whose domain is $mathbb N$, but the object that you describe (a) has no first term, and (b) terminates.



        If you want, I suppose you could define an object whose indices run from $-infty$ to $0$, but that's not appreciably different from looking at the original sequence while standing on your head.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Mar 8 at 3:27

























        answered Mar 8 at 1:49









        J. MurrayJ. Murray

        55017




        55017



























            draft saved

            draft discarded
















































            Thanks for contributing an answer to Mathematics Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3139613%2fis-there-such-a-thing-in-math-the-inverse-of-a-sequence%23new-answer', 'question_page');

            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            1928 у кіно

            Захаров Федір Захарович

            Ель Греко