Line integral in proof of Green's theorem












0












$begingroup$


In wikipedia page about Green's theorem the following equality appears:



$$
int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)), dx
$$



I do not understand it. Wikipedia page about line integral defines line integral, when applied to an scalar function, as:



$$
int_{mathcal{C}} f(mathbf{r}), ds = int_a^b fleft(mathbf{r}(t)right)|mathbf{r}'(t)| , dt.
$$



that, applied to the proof expression and taken into account that the curve $C_1$ has been parametrized as $(x,g_1(x))$, gives (?):



$$
int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)) ,, |(1,g_1'(x)| ,, dx
$$



that seems different to the one said in the proof (all curve derivative term has been supresed).










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    In wikipedia page about Green's theorem the following equality appears:



    $$
    int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)), dx
    $$



    I do not understand it. Wikipedia page about line integral defines line integral, when applied to an scalar function, as:



    $$
    int_{mathcal{C}} f(mathbf{r}), ds = int_a^b fleft(mathbf{r}(t)right)|mathbf{r}'(t)| , dt.
    $$



    that, applied to the proof expression and taken into account that the curve $C_1$ has been parametrized as $(x,g_1(x))$, gives (?):



    $$
    int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)) ,, |(1,g_1'(x)| ,, dx
    $$



    that seems different to the one said in the proof (all curve derivative term has been supresed).










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      In wikipedia page about Green's theorem the following equality appears:



      $$
      int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)), dx
      $$



      I do not understand it. Wikipedia page about line integral defines line integral, when applied to an scalar function, as:



      $$
      int_{mathcal{C}} f(mathbf{r}), ds = int_a^b fleft(mathbf{r}(t)right)|mathbf{r}'(t)| , dt.
      $$



      that, applied to the proof expression and taken into account that the curve $C_1$ has been parametrized as $(x,g_1(x))$, gives (?):



      $$
      int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)) ,, |(1,g_1'(x)| ,, dx
      $$



      that seems different to the one said in the proof (all curve derivative term has been supresed).










      share|cite|improve this question









      $endgroup$




      In wikipedia page about Green's theorem the following equality appears:



      $$
      int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)), dx
      $$



      I do not understand it. Wikipedia page about line integral defines line integral, when applied to an scalar function, as:



      $$
      int_{mathcal{C}} f(mathbf{r}), ds = int_a^b fleft(mathbf{r}(t)right)|mathbf{r}'(t)| , dt.
      $$



      that, applied to the proof expression and taken into account that the curve $C_1$ has been parametrized as $(x,g_1(x))$, gives (?):



      $$
      int_{C_1} L(x,y), dx = int_a^b L(x,g_1(x)) ,, |(1,g_1'(x)| ,, dx
      $$



      that seems different to the one said in the proof (all curve derivative term has been supresed).







      calculus line-integrals greens-theorem






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Dec 22 '18 at 18:54









      pasaba por aquipasaba por aqui

      454316




      454316






















          1 Answer
          1






          active

          oldest

          votes


















          1












          $begingroup$

          Note that one integral is a $ds$ integral and the other integral is a $dx$ integral. Here, Green's Theorem is written in the $int L,dx+M,dy$ form.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 19:00








          • 1




            $begingroup$
            @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
            $endgroup$
            – saulspatz
            Dec 22 '18 at 19:59










          • $begingroup$
            @saulspatz: thanks a lot
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 21:51












          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%2f3049745%2fline-integral-in-proof-of-greens-theorem%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












          $begingroup$

          Note that one integral is a $ds$ integral and the other integral is a $dx$ integral. Here, Green's Theorem is written in the $int L,dx+M,dy$ form.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 19:00








          • 1




            $begingroup$
            @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
            $endgroup$
            – saulspatz
            Dec 22 '18 at 19:59










          • $begingroup$
            @saulspatz: thanks a lot
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 21:51
















          1












          $begingroup$

          Note that one integral is a $ds$ integral and the other integral is a $dx$ integral. Here, Green's Theorem is written in the $int L,dx+M,dy$ form.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 19:00








          • 1




            $begingroup$
            @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
            $endgroup$
            – saulspatz
            Dec 22 '18 at 19:59










          • $begingroup$
            @saulspatz: thanks a lot
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 21:51














          1












          1








          1





          $begingroup$

          Note that one integral is a $ds$ integral and the other integral is a $dx$ integral. Here, Green's Theorem is written in the $int L,dx+M,dy$ form.






          share|cite|improve this answer









          $endgroup$



          Note that one integral is a $ds$ integral and the other integral is a $dx$ integral. Here, Green's Theorem is written in the $int L,dx+M,dy$ form.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 22 '18 at 18:56









          Ted ShifrinTed Shifrin

          64.6k44692




          64.6k44692












          • $begingroup$
            Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 19:00








          • 1




            $begingroup$
            @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
            $endgroup$
            – saulspatz
            Dec 22 '18 at 19:59










          • $begingroup$
            @saulspatz: thanks a lot
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 21:51


















          • $begingroup$
            Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 19:00








          • 1




            $begingroup$
            @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
            $endgroup$
            – saulspatz
            Dec 22 '18 at 19:59










          • $begingroup$
            @saulspatz: thanks a lot
            $endgroup$
            – pasaba por aqui
            Dec 22 '18 at 21:51
















          $begingroup$
          Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
          $endgroup$
          – pasaba por aqui
          Dec 22 '18 at 19:00






          $begingroup$
          Thanks for your answer. What is the dx integral of an scalar function over a curve $C_1$ ?
          $endgroup$
          – pasaba por aqui
          Dec 22 '18 at 19:00






          1




          1




          $begingroup$
          @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
          $endgroup$
          – saulspatz
          Dec 22 '18 at 19:59




          $begingroup$
          @pasabaporaqui Look at tutorial.math.lamar.edu/Classes/CalcIII/LineIntegralsPtII.aspx Contrast it with the previous part on line integrals with respect to arc length.
          $endgroup$
          – saulspatz
          Dec 22 '18 at 19:59












          $begingroup$
          @saulspatz: thanks a lot
          $endgroup$
          – pasaba por aqui
          Dec 22 '18 at 21:51




          $begingroup$
          @saulspatz: thanks a lot
          $endgroup$
          – pasaba por aqui
          Dec 22 '18 at 21:51


















          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%2f3049745%2fline-integral-in-proof-of-greens-theorem%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

          Le Mesnil-Réaume

          Ida-Boy-Ed-Garten

          web3.py web3.isConnected() returns false always