Learning about functions containing derivatives?












0












$begingroup$


Ideally, I'm looking to "solve" $$f(x)=x-f'(x-s),quad where,, x ,>=0,quad s=1, quad and quad f(-s) = 0$$
and the moving on to the same format but this equation instead:
$$f(x)=sign(x)-sign(f'(x-s))$$
But I ended up with a ton of questions while attempting to solve it. I'd break it into smaller questions but they seem to my untrained eye to be simple answers about properties on functions of this type.




  1. As far as I can tell this is a chaotic function? So there is no solution correct?

  2. Is this generally true of any function containing the derivative of
    a translated copy? I know it's not generally true if we remove the
    translation.

  3. Is there a name for this "recursive derivative" so I
    can research more about it, or is it just a blanket term of
    differential equation?

  4. I noticed that no matter how I calculated the
    sequence, as long as the spacing was even the generated sequence was
    identical for each term (scaled based on $s$), so f(1) depends on the
    spacing used to get there, not sensitivity to initial conditions, or even accuracy, is there a name for this property, and/or is the $s$ spacing considered
    part of initial conditions?


Assuming I didn't define the function correctly, here's the first few terms:
$$0,1,1,3,2,6,2,11,-1,21,-12,44,-44,101,-131,247$$










share|cite|improve this question











$endgroup$

















    0












    $begingroup$


    Ideally, I'm looking to "solve" $$f(x)=x-f'(x-s),quad where,, x ,>=0,quad s=1, quad and quad f(-s) = 0$$
    and the moving on to the same format but this equation instead:
    $$f(x)=sign(x)-sign(f'(x-s))$$
    But I ended up with a ton of questions while attempting to solve it. I'd break it into smaller questions but they seem to my untrained eye to be simple answers about properties on functions of this type.




    1. As far as I can tell this is a chaotic function? So there is no solution correct?

    2. Is this generally true of any function containing the derivative of
      a translated copy? I know it's not generally true if we remove the
      translation.

    3. Is there a name for this "recursive derivative" so I
      can research more about it, or is it just a blanket term of
      differential equation?

    4. I noticed that no matter how I calculated the
      sequence, as long as the spacing was even the generated sequence was
      identical for each term (scaled based on $s$), so f(1) depends on the
      spacing used to get there, not sensitivity to initial conditions, or even accuracy, is there a name for this property, and/or is the $s$ spacing considered
      part of initial conditions?


    Assuming I didn't define the function correctly, here's the first few terms:
    $$0,1,1,3,2,6,2,11,-1,21,-12,44,-44,101,-131,247$$










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      Ideally, I'm looking to "solve" $$f(x)=x-f'(x-s),quad where,, x ,>=0,quad s=1, quad and quad f(-s) = 0$$
      and the moving on to the same format but this equation instead:
      $$f(x)=sign(x)-sign(f'(x-s))$$
      But I ended up with a ton of questions while attempting to solve it. I'd break it into smaller questions but they seem to my untrained eye to be simple answers about properties on functions of this type.




      1. As far as I can tell this is a chaotic function? So there is no solution correct?

      2. Is this generally true of any function containing the derivative of
        a translated copy? I know it's not generally true if we remove the
        translation.

      3. Is there a name for this "recursive derivative" so I
        can research more about it, or is it just a blanket term of
        differential equation?

      4. I noticed that no matter how I calculated the
        sequence, as long as the spacing was even the generated sequence was
        identical for each term (scaled based on $s$), so f(1) depends on the
        spacing used to get there, not sensitivity to initial conditions, or even accuracy, is there a name for this property, and/or is the $s$ spacing considered
        part of initial conditions?


      Assuming I didn't define the function correctly, here's the first few terms:
      $$0,1,1,3,2,6,2,11,-1,21,-12,44,-44,101,-131,247$$










      share|cite|improve this question











      $endgroup$




      Ideally, I'm looking to "solve" $$f(x)=x-f'(x-s),quad where,, x ,>=0,quad s=1, quad and quad f(-s) = 0$$
      and the moving on to the same format but this equation instead:
      $$f(x)=sign(x)-sign(f'(x-s))$$
      But I ended up with a ton of questions while attempting to solve it. I'd break it into smaller questions but they seem to my untrained eye to be simple answers about properties on functions of this type.




      1. As far as I can tell this is a chaotic function? So there is no solution correct?

      2. Is this generally true of any function containing the derivative of
        a translated copy? I know it's not generally true if we remove the
        translation.

      3. Is there a name for this "recursive derivative" so I
        can research more about it, or is it just a blanket term of
        differential equation?

      4. I noticed that no matter how I calculated the
        sequence, as long as the spacing was even the generated sequence was
        identical for each term (scaled based on $s$), so f(1) depends on the
        spacing used to get there, not sensitivity to initial conditions, or even accuracy, is there a name for this property, and/or is the $s$ spacing considered
        part of initial conditions?


      Assuming I didn't define the function correctly, here's the first few terms:
      $$0,1,1,3,2,6,2,11,-1,21,-12,44,-44,101,-131,247$$







      derivatives






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 4 '18 at 12:45







      Black

















      asked Dec 4 '18 at 11:24









      BlackBlack

      1046




      1046






















          0






          active

          oldest

          votes











          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%2f3025442%2flearning-about-functions-containing-derivatives%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          0






          active

          oldest

          votes








          0






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          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%2f3025442%2flearning-about-functions-containing-derivatives%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

          Plaza Victoria

          In PowerPoint, is there a keyboard shortcut for bulleted / numbered list?

          How to put 3 figures in Latex with 2 figures side by side and 1 below these side by side images but in...