Find the limit $limlimits_{n to infty}sum_{k=1}^n frac{sqrt{4n+5k}}{n sqrt{n}} $












1












$begingroup$


I got stuck on the following limit:



$limlimits_{n to infty}5sum_{k=1}^n frac{sqrt{4n+5k}}{n sqrt{n}} $



The expected answer is $frac{38}{15}.$ Any hint is appreciated. Thanks



EDIT: The task is from this polish textbook (http://lucc.pl/inf/analiza_1/gewert_skoczylas__analiza_matematyczna_1__definicje_twierdzenia_wzory.pdf). It's on page 166 of the book (ex. 8.4.3 h). I want to compute this using the above fact. It's a book for first year students.










share|cite|improve this question











$endgroup$












  • $begingroup$
    If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
    $endgroup$
    – Stefan Lafon
    Jan 25 at 20:12










  • $begingroup$
    Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
    $endgroup$
    – The Cat
    Jan 25 at 20:15
















1












$begingroup$


I got stuck on the following limit:



$limlimits_{n to infty}5sum_{k=1}^n frac{sqrt{4n+5k}}{n sqrt{n}} $



The expected answer is $frac{38}{15}.$ Any hint is appreciated. Thanks



EDIT: The task is from this polish textbook (http://lucc.pl/inf/analiza_1/gewert_skoczylas__analiza_matematyczna_1__definicje_twierdzenia_wzory.pdf). It's on page 166 of the book (ex. 8.4.3 h). I want to compute this using the above fact. It's a book for first year students.










share|cite|improve this question











$endgroup$












  • $begingroup$
    If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
    $endgroup$
    – Stefan Lafon
    Jan 25 at 20:12










  • $begingroup$
    Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
    $endgroup$
    – The Cat
    Jan 25 at 20:15














1












1








1





$begingroup$


I got stuck on the following limit:



$limlimits_{n to infty}5sum_{k=1}^n frac{sqrt{4n+5k}}{n sqrt{n}} $



The expected answer is $frac{38}{15}.$ Any hint is appreciated. Thanks



EDIT: The task is from this polish textbook (http://lucc.pl/inf/analiza_1/gewert_skoczylas__analiza_matematyczna_1__definicje_twierdzenia_wzory.pdf). It's on page 166 of the book (ex. 8.4.3 h). I want to compute this using the above fact. It's a book for first year students.










share|cite|improve this question











$endgroup$




I got stuck on the following limit:



$limlimits_{n to infty}5sum_{k=1}^n frac{sqrt{4n+5k}}{n sqrt{n}} $



The expected answer is $frac{38}{15}.$ Any hint is appreciated. Thanks



EDIT: The task is from this polish textbook (http://lucc.pl/inf/analiza_1/gewert_skoczylas__analiza_matematyczna_1__definicje_twierdzenia_wzory.pdf). It's on page 166 of the book (ex. 8.4.3 h). I want to compute this using the above fact. It's a book for first year students.







limits summation






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 25 at 22:32







The Cat

















asked Jan 25 at 20:09









The CatThe Cat

33815




33815












  • $begingroup$
    If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
    $endgroup$
    – Stefan Lafon
    Jan 25 at 20:12










  • $begingroup$
    Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
    $endgroup$
    – The Cat
    Jan 25 at 20:15


















  • $begingroup$
    If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
    $endgroup$
    – Stefan Lafon
    Jan 25 at 20:12










  • $begingroup$
    Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
    $endgroup$
    – The Cat
    Jan 25 at 20:15
















$begingroup$
If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
$endgroup$
– Stefan Lafon
Jan 25 at 20:12




$begingroup$
If you rearrange the terms a bit, this is a Riemann sum. So it converges to some integral. Can you take it from there?
$endgroup$
– Stefan Lafon
Jan 25 at 20:12












$begingroup$
Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
$endgroup$
– The Cat
Jan 25 at 20:15




$begingroup$
Well this task here is from a prep-book to college. I've just started calculating definite integrals by definition, and in order to do the exercise i need to find this limit. I should be something way simpler.
$endgroup$
– The Cat
Jan 25 at 20:15










1 Answer
1






active

oldest

votes


















3












$begingroup$

Hint (Riemman Sum-Integral) :



$$lim_{n to infty} sum_{k=1}^n frac{sqrt{4n+5k}}{nsqrt{n}} = lim_{n to infty} frac{1}{n} sum_{k=1}^n sqrt{4 + 5frac{k}{n}} = int_0^1 sqrt{4 + 5x} ;mathrm{d}x$$






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%2f3087565%2ffind-the-limit-lim-limits-n-to-infty-sum-k-1n-frac-sqrt4n5kn-sq%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









    3












    $begingroup$

    Hint (Riemman Sum-Integral) :



    $$lim_{n to infty} sum_{k=1}^n frac{sqrt{4n+5k}}{nsqrt{n}} = lim_{n to infty} frac{1}{n} sum_{k=1}^n sqrt{4 + 5frac{k}{n}} = int_0^1 sqrt{4 + 5x} ;mathrm{d}x$$






    share|cite|improve this answer









    $endgroup$


















      3












      $begingroup$

      Hint (Riemman Sum-Integral) :



      $$lim_{n to infty} sum_{k=1}^n frac{sqrt{4n+5k}}{nsqrt{n}} = lim_{n to infty} frac{1}{n} sum_{k=1}^n sqrt{4 + 5frac{k}{n}} = int_0^1 sqrt{4 + 5x} ;mathrm{d}x$$






      share|cite|improve this answer









      $endgroup$
















        3












        3








        3





        $begingroup$

        Hint (Riemman Sum-Integral) :



        $$lim_{n to infty} sum_{k=1}^n frac{sqrt{4n+5k}}{nsqrt{n}} = lim_{n to infty} frac{1}{n} sum_{k=1}^n sqrt{4 + 5frac{k}{n}} = int_0^1 sqrt{4 + 5x} ;mathrm{d}x$$






        share|cite|improve this answer









        $endgroup$



        Hint (Riemman Sum-Integral) :



        $$lim_{n to infty} sum_{k=1}^n frac{sqrt{4n+5k}}{nsqrt{n}} = lim_{n to infty} frac{1}{n} sum_{k=1}^n sqrt{4 + 5frac{k}{n}} = int_0^1 sqrt{4 + 5x} ;mathrm{d}x$$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 25 at 20:12









        RebellosRebellos

        15.4k31250




        15.4k31250






























            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%2f3087565%2ffind-the-limit-lim-limits-n-to-infty-sum-k-1n-frac-sqrt4n5kn-sq%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

            android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

            SQL update select statement

            'app-layout' is not a known element: how to share Component with different Modules