Help:For what $ alpha $ do the integrals exist?












2














Let
$ K_R (y) subset mathbb{R}^n $
be an n-dimensional Ball with radius $R>0$ and midpoint $y in mathbb{R}^n $



Far what $ alpha in mathbb{R} $ and $ n in mathbb{N}{0} $ do following integrals exist:



$ int_{K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n setminus K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n } |x-y|^{alpha}dx $



with what criteria can i solve this task?
I don't know how to begin.
Thanks for any help!!



Let's take
$ int_{K{_R(y)}} |x-y|^{alpha}dx $ ,$y=0, n=2 $



If I replace by polarcoordinates $ x= rsin phi $ :
$ int_0^{2 pi} int_0^R | r|^{alpha} r dr dphi $..is this the right way?










share|cite|improve this question
























  • Take $y=0$ and $n=2$ to start. You can use polar coordinates.
    – zhw.
    Nov 28 '18 at 18:18
















2














Let
$ K_R (y) subset mathbb{R}^n $
be an n-dimensional Ball with radius $R>0$ and midpoint $y in mathbb{R}^n $



Far what $ alpha in mathbb{R} $ and $ n in mathbb{N}{0} $ do following integrals exist:



$ int_{K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n setminus K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n } |x-y|^{alpha}dx $



with what criteria can i solve this task?
I don't know how to begin.
Thanks for any help!!



Let's take
$ int_{K{_R(y)}} |x-y|^{alpha}dx $ ,$y=0, n=2 $



If I replace by polarcoordinates $ x= rsin phi $ :
$ int_0^{2 pi} int_0^R | r|^{alpha} r dr dphi $..is this the right way?










share|cite|improve this question
























  • Take $y=0$ and $n=2$ to start. You can use polar coordinates.
    – zhw.
    Nov 28 '18 at 18:18














2












2








2







Let
$ K_R (y) subset mathbb{R}^n $
be an n-dimensional Ball with radius $R>0$ and midpoint $y in mathbb{R}^n $



Far what $ alpha in mathbb{R} $ and $ n in mathbb{N}{0} $ do following integrals exist:



$ int_{K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n setminus K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n } |x-y|^{alpha}dx $



with what criteria can i solve this task?
I don't know how to begin.
Thanks for any help!!



Let's take
$ int_{K{_R(y)}} |x-y|^{alpha}dx $ ,$y=0, n=2 $



If I replace by polarcoordinates $ x= rsin phi $ :
$ int_0^{2 pi} int_0^R | r|^{alpha} r dr dphi $..is this the right way?










share|cite|improve this question















Let
$ K_R (y) subset mathbb{R}^n $
be an n-dimensional Ball with radius $R>0$ and midpoint $y in mathbb{R}^n $



Far what $ alpha in mathbb{R} $ and $ n in mathbb{N}{0} $ do following integrals exist:



$ int_{K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n setminus K{_R(y)}} |x-y|^{alpha}dx $



$ int_{ mathbb{R}^n } |x-y|^{alpha}dx $



with what criteria can i solve this task?
I don't know how to begin.
Thanks for any help!!



Let's take
$ int_{K{_R(y)}} |x-y|^{alpha}dx $ ,$y=0, n=2 $



If I replace by polarcoordinates $ x= rsin phi $ :
$ int_0^{2 pi} int_0^R | r|^{alpha} r dr dphi $..is this the right way?







real-analysis integration multivariable-calculus






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 28 '18 at 21:44







constant94

















asked Nov 28 '18 at 18:16









constant94constant94

1018




1018












  • Take $y=0$ and $n=2$ to start. You can use polar coordinates.
    – zhw.
    Nov 28 '18 at 18:18


















  • Take $y=0$ and $n=2$ to start. You can use polar coordinates.
    – zhw.
    Nov 28 '18 at 18:18
















Take $y=0$ and $n=2$ to start. You can use polar coordinates.
– zhw.
Nov 28 '18 at 18:18




Take $y=0$ and $n=2$ to start. You can use polar coordinates.
– zhw.
Nov 28 '18 at 18:18










1 Answer
1






active

oldest

votes


















1














Let $nomega_n$ denote the $n-1$ dimensional surface area of the $n-1$-sphere.



Your integrals, respectively, are
$$int_{K_R(y)} |x-y|^alpha , dx= int_0^R int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^R |x-y|^{n+alpha} , dr$$
$$int_{mathbb R^n setminus K_R(y)} |x-y|^alpha , dx= int_R^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_R^infty |x-y|^{n+alpha} , dr$$
$$int_{mathbb R^n} |x-y|^alpha , dx= int_0^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^infty|x-y|^{n+alpha} , dr$$
where $dx$ is the usual $n$-dimensional volume element in the integrals on the left and the $n-1$ dimensional surface area element in the integrals in the middle.



The remaining improper integrals are straight forward to work out.






share|cite|improve this answer





















    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%2f3017493%2fhelpfor-what-alpha-do-the-integrals-exist%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














    Let $nomega_n$ denote the $n-1$ dimensional surface area of the $n-1$-sphere.



    Your integrals, respectively, are
    $$int_{K_R(y)} |x-y|^alpha , dx= int_0^R int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^R |x-y|^{n+alpha} , dr$$
    $$int_{mathbb R^n setminus K_R(y)} |x-y|^alpha , dx= int_R^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_R^infty |x-y|^{n+alpha} , dr$$
    $$int_{mathbb R^n} |x-y|^alpha , dx= int_0^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^infty|x-y|^{n+alpha} , dr$$
    where $dx$ is the usual $n$-dimensional volume element in the integrals on the left and the $n-1$ dimensional surface area element in the integrals in the middle.



    The remaining improper integrals are straight forward to work out.






    share|cite|improve this answer


























      1














      Let $nomega_n$ denote the $n-1$ dimensional surface area of the $n-1$-sphere.



      Your integrals, respectively, are
      $$int_{K_R(y)} |x-y|^alpha , dx= int_0^R int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^R |x-y|^{n+alpha} , dr$$
      $$int_{mathbb R^n setminus K_R(y)} |x-y|^alpha , dx= int_R^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_R^infty |x-y|^{n+alpha} , dr$$
      $$int_{mathbb R^n} |x-y|^alpha , dx= int_0^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^infty|x-y|^{n+alpha} , dr$$
      where $dx$ is the usual $n$-dimensional volume element in the integrals on the left and the $n-1$ dimensional surface area element in the integrals in the middle.



      The remaining improper integrals are straight forward to work out.






      share|cite|improve this answer
























        1












        1








        1






        Let $nomega_n$ denote the $n-1$ dimensional surface area of the $n-1$-sphere.



        Your integrals, respectively, are
        $$int_{K_R(y)} |x-y|^alpha , dx= int_0^R int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^R |x-y|^{n+alpha} , dr$$
        $$int_{mathbb R^n setminus K_R(y)} |x-y|^alpha , dx= int_R^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_R^infty |x-y|^{n+alpha} , dr$$
        $$int_{mathbb R^n} |x-y|^alpha , dx= int_0^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^infty|x-y|^{n+alpha} , dr$$
        where $dx$ is the usual $n$-dimensional volume element in the integrals on the left and the $n-1$ dimensional surface area element in the integrals in the middle.



        The remaining improper integrals are straight forward to work out.






        share|cite|improve this answer












        Let $nomega_n$ denote the $n-1$ dimensional surface area of the $n-1$-sphere.



        Your integrals, respectively, are
        $$int_{K_R(y)} |x-y|^alpha , dx= int_0^R int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^R |x-y|^{n+alpha} , dr$$
        $$int_{mathbb R^n setminus K_R(y)} |x-y|^alpha , dx= int_R^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_R^infty |x-y|^{n+alpha} , dr$$
        $$int_{mathbb R^n} |x-y|^alpha , dx= int_0^infty int_{|x-y| = r} |x-y|^alpha , dx , dr = n omega_n int_0^infty|x-y|^{n+alpha} , dr$$
        where $dx$ is the usual $n$-dimensional volume element in the integrals on the left and the $n-1$ dimensional surface area element in the integrals in the middle.



        The remaining improper integrals are straight forward to work out.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 28 '18 at 21:52









        Umberto P.Umberto P.

        38.5k13064




        38.5k13064






























            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.





            Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


            Please pay close attention to the following guidance:


            • 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.


            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%2f3017493%2fhelpfor-what-alpha-do-the-integrals-exist%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

            Quarter-circle Tiles

            build a pushdown automaton that recognizes the reverse language of a given pushdown automaton?

            Mont Emei