Multiple integral equation with Barycentric coordinate












0












$begingroup$


$Delta(i, j, k)$ is a triangle with vertex $i(x_i, y_i), j(x_j, y_j), k(x_k, y_k)$ in counterclockwise, $P(x, y)$ is a point in $Delta(i, j, k)$, $S, S_i, S_j, S_k$ is the area of $Delta(i, j, k), Delta(j, k, P), Delta(k, i, P), Delta(i, j, P)$



triangle



we have $$left{begin{align}2S &= begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x_k & y_kend{vmatrix}, 2S_i = begin{vmatrix}1 & x & y \1 & x_j & y_j \1 & x_k & y_kend{vmatrix} \2S_j &= begin{vmatrix}1 & x_i & y_i \1 & x & y \1 & x_k & y_kend{vmatrix}, 2S_k = begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x & y end{vmatrix} end{align}right.$$



$P$'s barycentric coordinate is $(L_i, L_j, L_k)$
$$left{begin{align}L_i &= dfrac{S_i}{S} = dfrac{1}{2S}[(x_j y_k - x_k y_j) + (y_j - y_k)x + (x_k - x_j)y] \ L_j &= dfrac{S_j}{S} = dfrac{1}{2S}[(x_k y_i - x_i y_k) + (y_k - y_i)x + (x_i - x_k)y] \ L_k &= dfrac{S_k}{S} = dfrac{1}{2S}[(x_i y_j - x_j y_i) + (y_i - y_j)x + (x_j - x_i)y]end{align} right.$$
and
$$left{begin{align}x &= x_i L_i + x_j L_j + x_k L_k \ y &= y_i L_i + y_j L_j + y_k L_kend{align}right.$$



The problem is how to proof
$$begin{equation}iintlimits_{Delta(i, j, k)}L^p_i L^q_j L^r_k dxdy = 2Sdfrac{p!q!r!}{p + q + r + 2}end{equation}$$



I have replace $dxdy$ with $(x_i dL_i + x_j dL_j + x_k dL_k)(y_i dL_i + y_j dL_j + y_k dL_k)$ but still do not know how to continue.










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    $Delta(i, j, k)$ is a triangle with vertex $i(x_i, y_i), j(x_j, y_j), k(x_k, y_k)$ in counterclockwise, $P(x, y)$ is a point in $Delta(i, j, k)$, $S, S_i, S_j, S_k$ is the area of $Delta(i, j, k), Delta(j, k, P), Delta(k, i, P), Delta(i, j, P)$



    triangle



    we have $$left{begin{align}2S &= begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x_k & y_kend{vmatrix}, 2S_i = begin{vmatrix}1 & x & y \1 & x_j & y_j \1 & x_k & y_kend{vmatrix} \2S_j &= begin{vmatrix}1 & x_i & y_i \1 & x & y \1 & x_k & y_kend{vmatrix}, 2S_k = begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x & y end{vmatrix} end{align}right.$$



    $P$'s barycentric coordinate is $(L_i, L_j, L_k)$
    $$left{begin{align}L_i &= dfrac{S_i}{S} = dfrac{1}{2S}[(x_j y_k - x_k y_j) + (y_j - y_k)x + (x_k - x_j)y] \ L_j &= dfrac{S_j}{S} = dfrac{1}{2S}[(x_k y_i - x_i y_k) + (y_k - y_i)x + (x_i - x_k)y] \ L_k &= dfrac{S_k}{S} = dfrac{1}{2S}[(x_i y_j - x_j y_i) + (y_i - y_j)x + (x_j - x_i)y]end{align} right.$$
    and
    $$left{begin{align}x &= x_i L_i + x_j L_j + x_k L_k \ y &= y_i L_i + y_j L_j + y_k L_kend{align}right.$$



    The problem is how to proof
    $$begin{equation}iintlimits_{Delta(i, j, k)}L^p_i L^q_j L^r_k dxdy = 2Sdfrac{p!q!r!}{p + q + r + 2}end{equation}$$



    I have replace $dxdy$ with $(x_i dL_i + x_j dL_j + x_k dL_k)(y_i dL_i + y_j dL_j + y_k dL_k)$ but still do not know how to continue.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      $Delta(i, j, k)$ is a triangle with vertex $i(x_i, y_i), j(x_j, y_j), k(x_k, y_k)$ in counterclockwise, $P(x, y)$ is a point in $Delta(i, j, k)$, $S, S_i, S_j, S_k$ is the area of $Delta(i, j, k), Delta(j, k, P), Delta(k, i, P), Delta(i, j, P)$



      triangle



      we have $$left{begin{align}2S &= begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x_k & y_kend{vmatrix}, 2S_i = begin{vmatrix}1 & x & y \1 & x_j & y_j \1 & x_k & y_kend{vmatrix} \2S_j &= begin{vmatrix}1 & x_i & y_i \1 & x & y \1 & x_k & y_kend{vmatrix}, 2S_k = begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x & y end{vmatrix} end{align}right.$$



      $P$'s barycentric coordinate is $(L_i, L_j, L_k)$
      $$left{begin{align}L_i &= dfrac{S_i}{S} = dfrac{1}{2S}[(x_j y_k - x_k y_j) + (y_j - y_k)x + (x_k - x_j)y] \ L_j &= dfrac{S_j}{S} = dfrac{1}{2S}[(x_k y_i - x_i y_k) + (y_k - y_i)x + (x_i - x_k)y] \ L_k &= dfrac{S_k}{S} = dfrac{1}{2S}[(x_i y_j - x_j y_i) + (y_i - y_j)x + (x_j - x_i)y]end{align} right.$$
      and
      $$left{begin{align}x &= x_i L_i + x_j L_j + x_k L_k \ y &= y_i L_i + y_j L_j + y_k L_kend{align}right.$$



      The problem is how to proof
      $$begin{equation}iintlimits_{Delta(i, j, k)}L^p_i L^q_j L^r_k dxdy = 2Sdfrac{p!q!r!}{p + q + r + 2}end{equation}$$



      I have replace $dxdy$ with $(x_i dL_i + x_j dL_j + x_k dL_k)(y_i dL_i + y_j dL_j + y_k dL_k)$ but still do not know how to continue.










      share|cite|improve this question









      $endgroup$




      $Delta(i, j, k)$ is a triangle with vertex $i(x_i, y_i), j(x_j, y_j), k(x_k, y_k)$ in counterclockwise, $P(x, y)$ is a point in $Delta(i, j, k)$, $S, S_i, S_j, S_k$ is the area of $Delta(i, j, k), Delta(j, k, P), Delta(k, i, P), Delta(i, j, P)$



      triangle



      we have $$left{begin{align}2S &= begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x_k & y_kend{vmatrix}, 2S_i = begin{vmatrix}1 & x & y \1 & x_j & y_j \1 & x_k & y_kend{vmatrix} \2S_j &= begin{vmatrix}1 & x_i & y_i \1 & x & y \1 & x_k & y_kend{vmatrix}, 2S_k = begin{vmatrix}1 & x_i & y_i \1 & x_j & y_j \1 & x & y end{vmatrix} end{align}right.$$



      $P$'s barycentric coordinate is $(L_i, L_j, L_k)$
      $$left{begin{align}L_i &= dfrac{S_i}{S} = dfrac{1}{2S}[(x_j y_k - x_k y_j) + (y_j - y_k)x + (x_k - x_j)y] \ L_j &= dfrac{S_j}{S} = dfrac{1}{2S}[(x_k y_i - x_i y_k) + (y_k - y_i)x + (x_i - x_k)y] \ L_k &= dfrac{S_k}{S} = dfrac{1}{2S}[(x_i y_j - x_j y_i) + (y_i - y_j)x + (x_j - x_i)y]end{align} right.$$
      and
      $$left{begin{align}x &= x_i L_i + x_j L_j + x_k L_k \ y &= y_i L_i + y_j L_j + y_k L_kend{align}right.$$



      The problem is how to proof
      $$begin{equation}iintlimits_{Delta(i, j, k)}L^p_i L^q_j L^r_k dxdy = 2Sdfrac{p!q!r!}{p + q + r + 2}end{equation}$$



      I have replace $dxdy$ with $(x_i dL_i + x_j dL_j + x_k dL_k)(y_i dL_i + y_j dL_j + y_k dL_k)$ but still do not know how to continue.







      integration barycentric-coordinates






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 3 at 9:00









      BluedropsBluedrops

      136




      136






















          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%2f3060382%2fmultiple-integral-equation-with-barycentric-coordinate%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%2f3060382%2fmultiple-integral-equation-with-barycentric-coordinate%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

          Bressuire

          Cabo Verde

          Gyllenstierna