finding geometric multiplicity of a given matrix












1












$begingroup$


Let



$A =begin{bmatrix} a & 2f & 0 \ 2f & b & 3f \ 0 & 3f & c end{bmatrix}, tag 1$



where $a, b, c, f$ are real numbers and $f ne 0$. What is the geometric multiplicity of the largest eigenvalue of $A$?



For a symmetric matrix the geometric multiplicity equals algebraic multiplicity,so we can check the eigen values of the matrix but I find that difficult to solve. Is there any different approach to this problem ? Can anyone give some idea.
Thanks in advance.










share|cite|improve this question











$endgroup$












  • $begingroup$
    I edited your post to $LaTeX$ify it properly. Cheers!
    $endgroup$
    – Robert Lewis
    Dec 18 '18 at 17:51
















1












$begingroup$


Let



$A =begin{bmatrix} a & 2f & 0 \ 2f & b & 3f \ 0 & 3f & c end{bmatrix}, tag 1$



where $a, b, c, f$ are real numbers and $f ne 0$. What is the geometric multiplicity of the largest eigenvalue of $A$?



For a symmetric matrix the geometric multiplicity equals algebraic multiplicity,so we can check the eigen values of the matrix but I find that difficult to solve. Is there any different approach to this problem ? Can anyone give some idea.
Thanks in advance.










share|cite|improve this question











$endgroup$












  • $begingroup$
    I edited your post to $LaTeX$ify it properly. Cheers!
    $endgroup$
    – Robert Lewis
    Dec 18 '18 at 17:51














1












1








1





$begingroup$


Let



$A =begin{bmatrix} a & 2f & 0 \ 2f & b & 3f \ 0 & 3f & c end{bmatrix}, tag 1$



where $a, b, c, f$ are real numbers and $f ne 0$. What is the geometric multiplicity of the largest eigenvalue of $A$?



For a symmetric matrix the geometric multiplicity equals algebraic multiplicity,so we can check the eigen values of the matrix but I find that difficult to solve. Is there any different approach to this problem ? Can anyone give some idea.
Thanks in advance.










share|cite|improve this question











$endgroup$




Let



$A =begin{bmatrix} a & 2f & 0 \ 2f & b & 3f \ 0 & 3f & c end{bmatrix}, tag 1$



where $a, b, c, f$ are real numbers and $f ne 0$. What is the geometric multiplicity of the largest eigenvalue of $A$?



For a symmetric matrix the geometric multiplicity equals algebraic multiplicity,so we can check the eigen values of the matrix but I find that difficult to solve. Is there any different approach to this problem ? Can anyone give some idea.
Thanks in advance.







linear-algebra






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 18 '18 at 17:48









Robert Lewis

48.1k23167




48.1k23167










asked Dec 18 '18 at 17:01









math mathmath math

186




186












  • $begingroup$
    I edited your post to $LaTeX$ify it properly. Cheers!
    $endgroup$
    – Robert Lewis
    Dec 18 '18 at 17:51


















  • $begingroup$
    I edited your post to $LaTeX$ify it properly. Cheers!
    $endgroup$
    – Robert Lewis
    Dec 18 '18 at 17:51
















$begingroup$
I edited your post to $LaTeX$ify it properly. Cheers!
$endgroup$
– Robert Lewis
Dec 18 '18 at 17:51




$begingroup$
I edited your post to $LaTeX$ify it properly. Cheers!
$endgroup$
– Robert Lewis
Dec 18 '18 at 17:51










3 Answers
3






active

oldest

votes


















0












$begingroup$

Hint: If we can show that the matrix has distinct eigenvalues then, we can say that the geometric multiplicity of the largest eigen value is 1.






share|cite|improve this answer









$endgroup$





















    0












    $begingroup$

    Hint: If $lambda$ has the geometric multiplicity of $n,$ then
    $$
    begin{bmatrix}
    a-lambda & 2f & 0 \
    2f & b-lambda & 3f \
    0 & 3f & c-lambda
    end{bmatrix}
    $$

    has the rank $3-n.$



    A rank of $1$ means that each row (or each column) is a multiple of the same vector.



    A rank of $0$ means that the matrix is the zero-matrix.



    Can any of these happen?






    share|cite|improve this answer









    $endgroup$





















      0












      $begingroup$

      As you claimed, the matrix is symmetric hence diagonalizable, and thus is the geometric multiplicity of any eigenvalue equal to its algebraic multiplicity.



      If all $a,b,c,f$ are positive, by Perron-Frobenius theorem is the eigenvalue with the largest absolute value real and positive, and is simple (multiplicity 1). In other words, the spectral radius of the matrix is also an eigenvalue.






      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%2f3045405%2ffinding-geometric-multiplicity-of-a-given-matrix%23new-answer', 'question_page');
        }
        );

        Post as a guest















        Required, but never shown

























        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        0












        $begingroup$

        Hint: If we can show that the matrix has distinct eigenvalues then, we can say that the geometric multiplicity of the largest eigen value is 1.






        share|cite|improve this answer









        $endgroup$


















          0












          $begingroup$

          Hint: If we can show that the matrix has distinct eigenvalues then, we can say that the geometric multiplicity of the largest eigen value is 1.






          share|cite|improve this answer









          $endgroup$
















            0












            0








            0





            $begingroup$

            Hint: If we can show that the matrix has distinct eigenvalues then, we can say that the geometric multiplicity of the largest eigen value is 1.






            share|cite|improve this answer









            $endgroup$



            Hint: If we can show that the matrix has distinct eigenvalues then, we can say that the geometric multiplicity of the largest eigen value is 1.







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Jan 2 at 12:29









            shreyas s rshreyas s r

            1




            1























                0












                $begingroup$

                Hint: If $lambda$ has the geometric multiplicity of $n,$ then
                $$
                begin{bmatrix}
                a-lambda & 2f & 0 \
                2f & b-lambda & 3f \
                0 & 3f & c-lambda
                end{bmatrix}
                $$

                has the rank $3-n.$



                A rank of $1$ means that each row (or each column) is a multiple of the same vector.



                A rank of $0$ means that the matrix is the zero-matrix.



                Can any of these happen?






                share|cite|improve this answer









                $endgroup$


















                  0












                  $begingroup$

                  Hint: If $lambda$ has the geometric multiplicity of $n,$ then
                  $$
                  begin{bmatrix}
                  a-lambda & 2f & 0 \
                  2f & b-lambda & 3f \
                  0 & 3f & c-lambda
                  end{bmatrix}
                  $$

                  has the rank $3-n.$



                  A rank of $1$ means that each row (or each column) is a multiple of the same vector.



                  A rank of $0$ means that the matrix is the zero-matrix.



                  Can any of these happen?






                  share|cite|improve this answer









                  $endgroup$
















                    0












                    0








                    0





                    $begingroup$

                    Hint: If $lambda$ has the geometric multiplicity of $n,$ then
                    $$
                    begin{bmatrix}
                    a-lambda & 2f & 0 \
                    2f & b-lambda & 3f \
                    0 & 3f & c-lambda
                    end{bmatrix}
                    $$

                    has the rank $3-n.$



                    A rank of $1$ means that each row (or each column) is a multiple of the same vector.



                    A rank of $0$ means that the matrix is the zero-matrix.



                    Can any of these happen?






                    share|cite|improve this answer









                    $endgroup$



                    Hint: If $lambda$ has the geometric multiplicity of $n,$ then
                    $$
                    begin{bmatrix}
                    a-lambda & 2f & 0 \
                    2f & b-lambda & 3f \
                    0 & 3f & c-lambda
                    end{bmatrix}
                    $$

                    has the rank $3-n.$



                    A rank of $1$ means that each row (or each column) is a multiple of the same vector.



                    A rank of $0$ means that the matrix is the zero-matrix.



                    Can any of these happen?







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered Jan 2 at 15:35









                    Reinhard MeierReinhard Meier

                    2,912310




                    2,912310























                        0












                        $begingroup$

                        As you claimed, the matrix is symmetric hence diagonalizable, and thus is the geometric multiplicity of any eigenvalue equal to its algebraic multiplicity.



                        If all $a,b,c,f$ are positive, by Perron-Frobenius theorem is the eigenvalue with the largest absolute value real and positive, and is simple (multiplicity 1). In other words, the spectral radius of the matrix is also an eigenvalue.






                        share|cite|improve this answer









                        $endgroup$


















                          0












                          $begingroup$

                          As you claimed, the matrix is symmetric hence diagonalizable, and thus is the geometric multiplicity of any eigenvalue equal to its algebraic multiplicity.



                          If all $a,b,c,f$ are positive, by Perron-Frobenius theorem is the eigenvalue with the largest absolute value real and positive, and is simple (multiplicity 1). In other words, the spectral radius of the matrix is also an eigenvalue.






                          share|cite|improve this answer









                          $endgroup$
















                            0












                            0








                            0





                            $begingroup$

                            As you claimed, the matrix is symmetric hence diagonalizable, and thus is the geometric multiplicity of any eigenvalue equal to its algebraic multiplicity.



                            If all $a,b,c,f$ are positive, by Perron-Frobenius theorem is the eigenvalue with the largest absolute value real and positive, and is simple (multiplicity 1). In other words, the spectral radius of the matrix is also an eigenvalue.






                            share|cite|improve this answer









                            $endgroup$



                            As you claimed, the matrix is symmetric hence diagonalizable, and thus is the geometric multiplicity of any eigenvalue equal to its algebraic multiplicity.



                            If all $a,b,c,f$ are positive, by Perron-Frobenius theorem is the eigenvalue with the largest absolute value real and positive, and is simple (multiplicity 1). In other words, the spectral radius of the matrix is also an eigenvalue.







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered Jan 2 at 23:24









                            user376343user376343

                            3,9584829




                            3,9584829






























                                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%2f3045405%2ffinding-geometric-multiplicity-of-a-given-matrix%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