Partial derivative of a function defined in a rectangular area












0












$begingroup$


I noticed in a book that it considers a function $u(x,y)$ in the rectangular area : $xin (0, 1)$ ,$yin (0, 1]$, and takes there the $partial_y$. As I am used to only to take partial derivatives in open sets, I would appreciate a clarification of the value of $partial_y(x, 1)$. Is it $$partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$ or something else? Thanks in advance.










share|cite|improve this question











$endgroup$

















    0












    $begingroup$


    I noticed in a book that it considers a function $u(x,y)$ in the rectangular area : $xin (0, 1)$ ,$yin (0, 1]$, and takes there the $partial_y$. As I am used to only to take partial derivatives in open sets, I would appreciate a clarification of the value of $partial_y(x, 1)$. Is it $$partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$ or something else? Thanks in advance.










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      I noticed in a book that it considers a function $u(x,y)$ in the rectangular area : $xin (0, 1)$ ,$yin (0, 1]$, and takes there the $partial_y$. As I am used to only to take partial derivatives in open sets, I would appreciate a clarification of the value of $partial_y(x, 1)$. Is it $$partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$ or something else? Thanks in advance.










      share|cite|improve this question











      $endgroup$




      I noticed in a book that it considers a function $u(x,y)$ in the rectangular area : $xin (0, 1)$ ,$yin (0, 1]$, and takes there the $partial_y$. As I am used to only to take partial derivatives in open sets, I would appreciate a clarification of the value of $partial_y(x, 1)$. Is it $$partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$ or something else? Thanks in advance.







      calculus multivariable-calculus derivatives






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 4 at 3:59







      dmtri

















      asked Jan 3 at 15:13









      dmtridmtri

      1,5162521




      1,5162521






















          1 Answer
          1






          active

          oldest

          votes


















          2












          $begingroup$

          Yes, your definition of partial derivative with respect to $y$ at $(x,1)$



          $$ partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$



          is correct. Of course it is one sided because we do not have $y>1$ as part of the domain.






          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%2f3060648%2fpartial-derivative-of-a-function-defined-in-a-rectangular-area%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









            2












            $begingroup$

            Yes, your definition of partial derivative with respect to $y$ at $(x,1)$



            $$ partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$



            is correct. Of course it is one sided because we do not have $y>1$ as part of the domain.






            share|cite|improve this answer









            $endgroup$


















              2












              $begingroup$

              Yes, your definition of partial derivative with respect to $y$ at $(x,1)$



              $$ partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$



              is correct. Of course it is one sided because we do not have $y>1$ as part of the domain.






              share|cite|improve this answer









              $endgroup$
















                2












                2








                2





                $begingroup$

                Yes, your definition of partial derivative with respect to $y$ at $(x,1)$



                $$ partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$



                is correct. Of course it is one sided because we do not have $y>1$ as part of the domain.






                share|cite|improve this answer









                $endgroup$



                Yes, your definition of partial derivative with respect to $y$ at $(x,1)$



                $$ partial_y{u(x, 1)}=lim_{tto 1^{-}}frac{u(x, t) -u(x, 1)}{t-1}$$



                is correct. Of course it is one sided because we do not have $y>1$ as part of the domain.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 4 at 4:06









                Mohammad Riazi-KermaniMohammad Riazi-Kermani

                41.6k42061




                41.6k42061






























                    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%2f3060648%2fpartial-derivative-of-a-function-defined-in-a-rectangular-area%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

                    Ellipse (mathématiques)

                    Quarter-circle Tiles

                    Mont Emei