show that the height of the cylinder of maximum volume that can be inscribed within a cone of height $h$ is...











up vote
0
down vote

favorite












show that the height of the cylinder of maximum volume that can be inscribed within a cone of height $h$ is $frac{h}3$.



I have tried solving this sum but am unable to substitute the radius of the cylinder in terms of $h$.










share|cite|improve this question
























  • See this for finding the maximum volume of a cylinder in a cone of height $h$.
    – heather
    Mar 19 '17 at 13:03















up vote
0
down vote

favorite












show that the height of the cylinder of maximum volume that can be inscribed within a cone of height $h$ is $frac{h}3$.



I have tried solving this sum but am unable to substitute the radius of the cylinder in terms of $h$.










share|cite|improve this question
























  • See this for finding the maximum volume of a cylinder in a cone of height $h$.
    – heather
    Mar 19 '17 at 13:03













up vote
0
down vote

favorite









up vote
0
down vote

favorite











show that the height of the cylinder of maximum volume that can be inscribed within a cone of height $h$ is $frac{h}3$.



I have tried solving this sum but am unable to substitute the radius of the cylinder in terms of $h$.










share|cite|improve this question















show that the height of the cylinder of maximum volume that can be inscribed within a cone of height $h$ is $frac{h}3$.



I have tried solving this sum but am unable to substitute the radius of the cylinder in terms of $h$.







derivatives maxima-minima






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 27 '17 at 21:02









Siong Thye Goh

94.6k1462114




94.6k1462114










asked Mar 19 '17 at 12:40









Dhruv Raghunath

151212




151212












  • See this for finding the maximum volume of a cylinder in a cone of height $h$.
    – heather
    Mar 19 '17 at 13:03


















  • See this for finding the maximum volume of a cylinder in a cone of height $h$.
    – heather
    Mar 19 '17 at 13:03
















See this for finding the maximum volume of a cylinder in a cone of height $h$.
– heather
Mar 19 '17 at 13:03




See this for finding the maximum volume of a cylinder in a cone of height $h$.
– heather
Mar 19 '17 at 13:03










1 Answer
1






active

oldest

votes

















up vote
0
down vote













Hint:



enter image description here



Look at the figure. With:
$$
BH=h quad HC=R quad FG=x quad HG=r
$$



from the similarity of the triangles $BHC$ and $FGC$ we have:



$$
h:x=R:(R-r)
$$
so that $r=frac{R}{h}(h-x)$



Now you can express the volume of the cylinder as $V=pi r^2x=pi frac{R^2}{h^2}(h-x)^2x $.



Maximize this function.






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',
    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%2f2193469%2fshow-that-the-height-of-the-cylinder-of-maximum-volume-that-can-be-inscribed-wit%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








    up vote
    0
    down vote













    Hint:



    enter image description here



    Look at the figure. With:
    $$
    BH=h quad HC=R quad FG=x quad HG=r
    $$



    from the similarity of the triangles $BHC$ and $FGC$ we have:



    $$
    h:x=R:(R-r)
    $$
    so that $r=frac{R}{h}(h-x)$



    Now you can express the volume of the cylinder as $V=pi r^2x=pi frac{R^2}{h^2}(h-x)^2x $.



    Maximize this function.






    share|cite|improve this answer

























      up vote
      0
      down vote













      Hint:



      enter image description here



      Look at the figure. With:
      $$
      BH=h quad HC=R quad FG=x quad HG=r
      $$



      from the similarity of the triangles $BHC$ and $FGC$ we have:



      $$
      h:x=R:(R-r)
      $$
      so that $r=frac{R}{h}(h-x)$



      Now you can express the volume of the cylinder as $V=pi r^2x=pi frac{R^2}{h^2}(h-x)^2x $.



      Maximize this function.






      share|cite|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        Hint:



        enter image description here



        Look at the figure. With:
        $$
        BH=h quad HC=R quad FG=x quad HG=r
        $$



        from the similarity of the triangles $BHC$ and $FGC$ we have:



        $$
        h:x=R:(R-r)
        $$
        so that $r=frac{R}{h}(h-x)$



        Now you can express the volume of the cylinder as $V=pi r^2x=pi frac{R^2}{h^2}(h-x)^2x $.



        Maximize this function.






        share|cite|improve this answer












        Hint:



        enter image description here



        Look at the figure. With:
        $$
        BH=h quad HC=R quad FG=x quad HG=r
        $$



        from the similarity of the triangles $BHC$ and $FGC$ we have:



        $$
        h:x=R:(R-r)
        $$
        so that $r=frac{R}{h}(h-x)$



        Now you can express the volume of the cylinder as $V=pi r^2x=pi frac{R^2}{h^2}(h-x)^2x $.



        Maximize this function.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 19 '17 at 13:46









        Emilio Novati

        50.8k43472




        50.8k43472






























            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%2f2193469%2fshow-that-the-height-of-the-cylinder-of-maximum-volume-that-can-be-inscribed-wit%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

            Berounka

            Sphinx de Gizeh

            Different font size/position of beamer's navigation symbols template's content depending on regular/plain...