Infinite Series arising in Laplace transform












0












$begingroup$


I'm trying to understand how the answer was computed for the following infinite series:



$sum _ { x = 1 } ^ { infty } e ^ { - s x } p q ^ { x - 1 } = frac { p e ^ { - s } } { 1 - q e ^ { - s } }$



Any help would be highly appreciated.










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    I'm trying to understand how the answer was computed for the following infinite series:



    $sum _ { x = 1 } ^ { infty } e ^ { - s x } p q ^ { x - 1 } = frac { p e ^ { - s } } { 1 - q e ^ { - s } }$



    Any help would be highly appreciated.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      I'm trying to understand how the answer was computed for the following infinite series:



      $sum _ { x = 1 } ^ { infty } e ^ { - s x } p q ^ { x - 1 } = frac { p e ^ { - s } } { 1 - q e ^ { - s } }$



      Any help would be highly appreciated.










      share|cite|improve this question









      $endgroup$




      I'm trying to understand how the answer was computed for the following infinite series:



      $sum _ { x = 1 } ^ { infty } e ^ { - s x } p q ^ { x - 1 } = frac { p e ^ { - s } } { 1 - q e ^ { - s } }$



      Any help would be highly appreciated.







      sequences-and-series convergence power-series laplace-transform laurent-series






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 28 at 18:57









      AlexAlex

      115




      115






















          1 Answer
          1






          active

          oldest

          votes


















          0












          $begingroup$

          Hint: $e^{-sx}pq^{x-1}=(e^{-s}q)^{x-1} cdot pe^{-s}$. You know the sum of a geometric series, right?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
            $endgroup$
            – Alex
            Jan 28 at 19:27












          • $begingroup$
            I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
            $endgroup$
            – Alex
            Jan 28 at 19:35














          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%2f3091254%2finfinite-series-arising-in-laplace-transform%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









          0












          $begingroup$

          Hint: $e^{-sx}pq^{x-1}=(e^{-s}q)^{x-1} cdot pe^{-s}$. You know the sum of a geometric series, right?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
            $endgroup$
            – Alex
            Jan 28 at 19:27












          • $begingroup$
            I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
            $endgroup$
            – Alex
            Jan 28 at 19:35


















          0












          $begingroup$

          Hint: $e^{-sx}pq^{x-1}=(e^{-s}q)^{x-1} cdot pe^{-s}$. You know the sum of a geometric series, right?






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
            $endgroup$
            – Alex
            Jan 28 at 19:27












          • $begingroup$
            I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
            $endgroup$
            – Alex
            Jan 28 at 19:35
















          0












          0








          0





          $begingroup$

          Hint: $e^{-sx}pq^{x-1}=(e^{-s}q)^{x-1} cdot pe^{-s}$. You know the sum of a geometric series, right?






          share|cite|improve this answer











          $endgroup$



          Hint: $e^{-sx}pq^{x-1}=(e^{-s}q)^{x-1} cdot pe^{-s}$. You know the sum of a geometric series, right?







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Jan 28 at 19:14

























          answered Jan 28 at 19:05









          MindlackMindlack

          4,910211




          4,910211












          • $begingroup$
            Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
            $endgroup$
            – Alex
            Jan 28 at 19:27












          • $begingroup$
            I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
            $endgroup$
            – Alex
            Jan 28 at 19:35




















          • $begingroup$
            Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
            $endgroup$
            – Alex
            Jan 28 at 19:27












          • $begingroup$
            I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
            $endgroup$
            – Alex
            Jan 28 at 19:35


















          $begingroup$
          Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
          $endgroup$
          – Alex
          Jan 28 at 19:27






          $begingroup$
          Thanks for the hint @Mindlack. I know very little about geometric series (and series in general) though. I guess this now should look like some expression for which the sum is well known. I will try to compute this using online solver (although it could not give me an answer for the original form).
          $endgroup$
          – Alex
          Jan 28 at 19:27














          $begingroup$
          I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
          $endgroup$
          – Alex
          Jan 28 at 19:35






          $begingroup$
          I got it now :), many thanks @Mindlack. Just needed to replace accordingly in $S _ { infty } = sum _ { n = 1 } ^ { infty } a r ^ { n - 1 } = frac { a _ { } } { 1 - r ^ { } }$
          $endgroup$
          – Alex
          Jan 28 at 19:35




















          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%2f3091254%2finfinite-series-arising-in-laplace-transform%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

          The term 'EXEC' is not recognized as the name of a cmdlet Powershell

          NPM command prompt closes immediately [closed]

          Error binding properties and functions in emscripten