Find the Recurrence relation for $q_n$ given the following condition:












1












$begingroup$


Let $q_n$ denote the number of strings of length $n$ (formed from digits 0,1,2,3) which have even number of $2$'s. set up a recurrence relation for $q_n$.










share|cite|improve this question











$endgroup$

















    1












    $begingroup$


    Let $q_n$ denote the number of strings of length $n$ (formed from digits 0,1,2,3) which have even number of $2$'s. set up a recurrence relation for $q_n$.










    share|cite|improve this question











    $endgroup$















      1












      1








      1


      2



      $begingroup$


      Let $q_n$ denote the number of strings of length $n$ (formed from digits 0,1,2,3) which have even number of $2$'s. set up a recurrence relation for $q_n$.










      share|cite|improve this question











      $endgroup$




      Let $q_n$ denote the number of strings of length $n$ (formed from digits 0,1,2,3) which have even number of $2$'s. set up a recurrence relation for $q_n$.







      discrete-mathematics recurrence-relations generating-functions






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 10 '18 at 9:19







      Cosmic

















      asked Dec 10 '18 at 8:54









      CosmicCosmic

      8810




      8810






















          1 Answer
          1






          active

          oldest

          votes


















          0












          $begingroup$

          Indeed it can be defined by two recurrence. Suppose $p_n$ is the number of strings which have odd 2's. Now we have:
          $$q_n = 3q_{n-1} + p_{n-1}$$
          $$p_n = q_{n-1} + 3 p_{n-1}$$



          Now we can unified them by matrix operation by $T_n = begin{bmatrix}q_n \ p_n end{bmatrix}$:



          $$T_n=begin{bmatrix}3 & 0 \ 0 & 1 end{bmatrix}T_{n-1}+begin{bmatrix}0 & 1 \ 3 & 0 end{bmatrix}T_{n-1}=begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}T_{n-1}.$$



          Now we can say $T_n = begin{bmatrix}q_n \ p_n end{bmatrix} = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}T_1$. We can compute that $T_1 = begin{bmatrix}3 \ 1 end{bmatrix}$, and
          $$T_n = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}begin{bmatrix}3 \ 1 end{bmatrix}$$






          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%2f3033660%2ffind-the-recurrence-relation-for-q-n-given-the-following-condition%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












            $begingroup$

            Indeed it can be defined by two recurrence. Suppose $p_n$ is the number of strings which have odd 2's. Now we have:
            $$q_n = 3q_{n-1} + p_{n-1}$$
            $$p_n = q_{n-1} + 3 p_{n-1}$$



            Now we can unified them by matrix operation by $T_n = begin{bmatrix}q_n \ p_n end{bmatrix}$:



            $$T_n=begin{bmatrix}3 & 0 \ 0 & 1 end{bmatrix}T_{n-1}+begin{bmatrix}0 & 1 \ 3 & 0 end{bmatrix}T_{n-1}=begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}T_{n-1}.$$



            Now we can say $T_n = begin{bmatrix}q_n \ p_n end{bmatrix} = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}T_1$. We can compute that $T_1 = begin{bmatrix}3 \ 1 end{bmatrix}$, and
            $$T_n = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}begin{bmatrix}3 \ 1 end{bmatrix}$$






            share|cite|improve this answer











            $endgroup$


















              0












              $begingroup$

              Indeed it can be defined by two recurrence. Suppose $p_n$ is the number of strings which have odd 2's. Now we have:
              $$q_n = 3q_{n-1} + p_{n-1}$$
              $$p_n = q_{n-1} + 3 p_{n-1}$$



              Now we can unified them by matrix operation by $T_n = begin{bmatrix}q_n \ p_n end{bmatrix}$:



              $$T_n=begin{bmatrix}3 & 0 \ 0 & 1 end{bmatrix}T_{n-1}+begin{bmatrix}0 & 1 \ 3 & 0 end{bmatrix}T_{n-1}=begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}T_{n-1}.$$



              Now we can say $T_n = begin{bmatrix}q_n \ p_n end{bmatrix} = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}T_1$. We can compute that $T_1 = begin{bmatrix}3 \ 1 end{bmatrix}$, and
              $$T_n = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}begin{bmatrix}3 \ 1 end{bmatrix}$$






              share|cite|improve this answer











              $endgroup$
















                0












                0








                0





                $begingroup$

                Indeed it can be defined by two recurrence. Suppose $p_n$ is the number of strings which have odd 2's. Now we have:
                $$q_n = 3q_{n-1} + p_{n-1}$$
                $$p_n = q_{n-1} + 3 p_{n-1}$$



                Now we can unified them by matrix operation by $T_n = begin{bmatrix}q_n \ p_n end{bmatrix}$:



                $$T_n=begin{bmatrix}3 & 0 \ 0 & 1 end{bmatrix}T_{n-1}+begin{bmatrix}0 & 1 \ 3 & 0 end{bmatrix}T_{n-1}=begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}T_{n-1}.$$



                Now we can say $T_n = begin{bmatrix}q_n \ p_n end{bmatrix} = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}T_1$. We can compute that $T_1 = begin{bmatrix}3 \ 1 end{bmatrix}$, and
                $$T_n = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}begin{bmatrix}3 \ 1 end{bmatrix}$$






                share|cite|improve this answer











                $endgroup$



                Indeed it can be defined by two recurrence. Suppose $p_n$ is the number of strings which have odd 2's. Now we have:
                $$q_n = 3q_{n-1} + p_{n-1}$$
                $$p_n = q_{n-1} + 3 p_{n-1}$$



                Now we can unified them by matrix operation by $T_n = begin{bmatrix}q_n \ p_n end{bmatrix}$:



                $$T_n=begin{bmatrix}3 & 0 \ 0 & 1 end{bmatrix}T_{n-1}+begin{bmatrix}0 & 1 \ 3 & 0 end{bmatrix}T_{n-1}=begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}T_{n-1}.$$



                Now we can say $T_n = begin{bmatrix}q_n \ p_n end{bmatrix} = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}T_1$. We can compute that $T_1 = begin{bmatrix}3 \ 1 end{bmatrix}$, and
                $$T_n = begin{bmatrix}3 & 1 \ 3 & 1 end{bmatrix}^{n-1}begin{bmatrix}3 \ 1 end{bmatrix}$$







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Dec 10 '18 at 9:57

























                answered Dec 10 '18 at 9:49









                OmGOmG

                2,502822




                2,502822






























                    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%2f3033660%2ffind-the-recurrence-relation-for-q-n-given-the-following-condition%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

                    Bundesstraße 106

                    Ida-Boy-Ed-Garten