How to study the uniform convergence of $sumfrac{n^{n+1}x^{n}e^{-nx}}{n!} ? x geq 0$












-3












$begingroup$


How to study the uniform convergence of $$sumfrac{n^{n+1}x^{n}e^{-nx}}{n!} $$



I was thinking about the Weierstrass M-test, but if we consider as $$f_n(x) =frac{n^{n+1}x^{n}e^{-nx}}{n!}$$.



The $f_n(x)$ takes max. value at $x=1$ so we consider $$M_n=frac{n^{n+1}e^{-n}}{n!}$$ but $M_n$ does not converge.










share|cite|improve this question











$endgroup$












  • $begingroup$
    I would use the change of variable $t:=xe^x$.
    $endgroup$
    – Yves Daoust
    Jan 27 at 20:08






  • 1




    $begingroup$
    Please, show that you have worked on your exercise...
    $endgroup$
    – Jean Marie
    Jan 27 at 21:00










  • $begingroup$
    I have edited and changed a typing mistake
    $endgroup$
    – Thecomons
    Jan 27 at 21:12










  • $begingroup$
    uniform convergence where?
    $endgroup$
    – zhw.
    Jan 27 at 23:37










  • $begingroup$
    for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
    $endgroup$
    – Thecomons
    Jan 27 at 23:59
















-3












$begingroup$


How to study the uniform convergence of $$sumfrac{n^{n+1}x^{n}e^{-nx}}{n!} $$



I was thinking about the Weierstrass M-test, but if we consider as $$f_n(x) =frac{n^{n+1}x^{n}e^{-nx}}{n!}$$.



The $f_n(x)$ takes max. value at $x=1$ so we consider $$M_n=frac{n^{n+1}e^{-n}}{n!}$$ but $M_n$ does not converge.










share|cite|improve this question











$endgroup$












  • $begingroup$
    I would use the change of variable $t:=xe^x$.
    $endgroup$
    – Yves Daoust
    Jan 27 at 20:08






  • 1




    $begingroup$
    Please, show that you have worked on your exercise...
    $endgroup$
    – Jean Marie
    Jan 27 at 21:00










  • $begingroup$
    I have edited and changed a typing mistake
    $endgroup$
    – Thecomons
    Jan 27 at 21:12










  • $begingroup$
    uniform convergence where?
    $endgroup$
    – zhw.
    Jan 27 at 23:37










  • $begingroup$
    for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
    $endgroup$
    – Thecomons
    Jan 27 at 23:59














-3












-3








-3


1



$begingroup$


How to study the uniform convergence of $$sumfrac{n^{n+1}x^{n}e^{-nx}}{n!} $$



I was thinking about the Weierstrass M-test, but if we consider as $$f_n(x) =frac{n^{n+1}x^{n}e^{-nx}}{n!}$$.



The $f_n(x)$ takes max. value at $x=1$ so we consider $$M_n=frac{n^{n+1}e^{-n}}{n!}$$ but $M_n$ does not converge.










share|cite|improve this question











$endgroup$




How to study the uniform convergence of $$sumfrac{n^{n+1}x^{n}e^{-nx}}{n!} $$



I was thinking about the Weierstrass M-test, but if we consider as $$f_n(x) =frac{n^{n+1}x^{n}e^{-nx}}{n!}$$.



The $f_n(x)$ takes max. value at $x=1$ so we consider $$M_n=frac{n^{n+1}e^{-n}}{n!}$$ but $M_n$ does not converge.







real-analysis analysis






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 27 at 23:57







Thecomons

















asked Jan 27 at 20:06









ThecomonsThecomons

72




72












  • $begingroup$
    I would use the change of variable $t:=xe^x$.
    $endgroup$
    – Yves Daoust
    Jan 27 at 20:08






  • 1




    $begingroup$
    Please, show that you have worked on your exercise...
    $endgroup$
    – Jean Marie
    Jan 27 at 21:00










  • $begingroup$
    I have edited and changed a typing mistake
    $endgroup$
    – Thecomons
    Jan 27 at 21:12










  • $begingroup$
    uniform convergence where?
    $endgroup$
    – zhw.
    Jan 27 at 23:37










  • $begingroup$
    for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
    $endgroup$
    – Thecomons
    Jan 27 at 23:59


















  • $begingroup$
    I would use the change of variable $t:=xe^x$.
    $endgroup$
    – Yves Daoust
    Jan 27 at 20:08






  • 1




    $begingroup$
    Please, show that you have worked on your exercise...
    $endgroup$
    – Jean Marie
    Jan 27 at 21:00










  • $begingroup$
    I have edited and changed a typing mistake
    $endgroup$
    – Thecomons
    Jan 27 at 21:12










  • $begingroup$
    uniform convergence where?
    $endgroup$
    – zhw.
    Jan 27 at 23:37










  • $begingroup$
    for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
    $endgroup$
    – Thecomons
    Jan 27 at 23:59
















$begingroup$
I would use the change of variable $t:=xe^x$.
$endgroup$
– Yves Daoust
Jan 27 at 20:08




$begingroup$
I would use the change of variable $t:=xe^x$.
$endgroup$
– Yves Daoust
Jan 27 at 20:08




1




1




$begingroup$
Please, show that you have worked on your exercise...
$endgroup$
– Jean Marie
Jan 27 at 21:00




$begingroup$
Please, show that you have worked on your exercise...
$endgroup$
– Jean Marie
Jan 27 at 21:00












$begingroup$
I have edited and changed a typing mistake
$endgroup$
– Thecomons
Jan 27 at 21:12




$begingroup$
I have edited and changed a typing mistake
$endgroup$
– Thecomons
Jan 27 at 21:12












$begingroup$
uniform convergence where?
$endgroup$
– zhw.
Jan 27 at 23:37




$begingroup$
uniform convergence where?
$endgroup$
– zhw.
Jan 27 at 23:37












$begingroup$
for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
$endgroup$
– Thecomons
Jan 27 at 23:59




$begingroup$
for x >= 0. But probably i should closed the interval, for example $(0,a)$ idk
$endgroup$
– Thecomons
Jan 27 at 23:59










1 Answer
1






active

oldest

votes


















1












$begingroup$

Hint: Study pointwise convergence first with the ratio test.






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%2f3090051%2fhow-to-study-the-uniform-convergence-of-sum-fracnn1xne-nxn-x%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









    1












    $begingroup$

    Hint: Study pointwise convergence first with the ratio test.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      Hint: Study pointwise convergence first with the ratio test.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        Hint: Study pointwise convergence first with the ratio test.






        share|cite|improve this answer









        $endgroup$



        Hint: Study pointwise convergence first with the ratio test.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 28 at 0:49









        zhw.zhw.

        74.7k43175




        74.7k43175






























            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%2f3090051%2fhow-to-study-the-uniform-convergence-of-sum-fracnn1xne-nxn-x%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

            MongoDB - Not Authorized To Execute Command

            How to fix TextFormField cause rebuild widget in Flutter

            in spring boot 2.1 many test slices are not allowed anymore due to multiple @BootstrapWith