Find $lambda$ and solve the matrix












0












$begingroup$


Find $lambda$ and solve the matrix. I have 4 equations:



begin{cases}
x+y+z-t=2\
x+y-z+t=2\
3x+y+z+t=lambda\
x-y+z+t=2\
end{cases}

I've got $$t=frac{lambda -6}{4}; z=frac{6-lambda}{4}; y=frac{lambda -6}{4}; x=frac{2+lambda}{4}$$



What I did wrong?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Yes, it's wrong. Substitute it in the second equation.
    $endgroup$
    – Michael Rozenberg
    Jan 7 at 9:43
















0












$begingroup$


Find $lambda$ and solve the matrix. I have 4 equations:



begin{cases}
x+y+z-t=2\
x+y-z+t=2\
3x+y+z+t=lambda\
x-y+z+t=2\
end{cases}

I've got $$t=frac{lambda -6}{4}; z=frac{6-lambda}{4}; y=frac{lambda -6}{4}; x=frac{2+lambda}{4}$$



What I did wrong?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Yes, it's wrong. Substitute it in the second equation.
    $endgroup$
    – Michael Rozenberg
    Jan 7 at 9:43














0












0








0





$begingroup$


Find $lambda$ and solve the matrix. I have 4 equations:



begin{cases}
x+y+z-t=2\
x+y-z+t=2\
3x+y+z+t=lambda\
x-y+z+t=2\
end{cases}

I've got $$t=frac{lambda -6}{4}; z=frac{6-lambda}{4}; y=frac{lambda -6}{4}; x=frac{2+lambda}{4}$$



What I did wrong?










share|cite|improve this question











$endgroup$




Find $lambda$ and solve the matrix. I have 4 equations:



begin{cases}
x+y+z-t=2\
x+y-z+t=2\
3x+y+z+t=lambda\
x-y+z+t=2\
end{cases}

I've got $$t=frac{lambda -6}{4}; z=frac{6-lambda}{4}; y=frac{lambda -6}{4}; x=frac{2+lambda}{4}$$



What I did wrong?







matrices matrix-equations






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 7 at 10:06









Lorenzo B.

1,8402520




1,8402520










asked Jan 7 at 9:39









J.DoeJ.Doe

899




899












  • $begingroup$
    Yes, it's wrong. Substitute it in the second equation.
    $endgroup$
    – Michael Rozenberg
    Jan 7 at 9:43


















  • $begingroup$
    Yes, it's wrong. Substitute it in the second equation.
    $endgroup$
    – Michael Rozenberg
    Jan 7 at 9:43
















$begingroup$
Yes, it's wrong. Substitute it in the second equation.
$endgroup$
– Michael Rozenberg
Jan 7 at 9:43




$begingroup$
Yes, it's wrong. Substitute it in the second equation.
$endgroup$
– Michael Rozenberg
Jan 7 at 9:43










3 Answers
3






active

oldest

votes


















0












$begingroup$

After adding of the first, second and forth equations we'll get $$3x+y+z+t=6,$$ which gives $lambda=6.$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    But using Gauss I can't get this solution?
    $endgroup$
    – J.Doe
    Jan 7 at 10:00










  • $begingroup$
    @J.Doe Which says that there is a mistake in your computations.
    $endgroup$
    – Michael Rozenberg
    Jan 7 at 10:05



















0












$begingroup$

Hint: It is $$x=2-t,y=t,z=t$$ and $$lambda=6$$






share|cite|improve this answer









$endgroup$





















    0












    $begingroup$

    Subtracting eq. 2 from both eq. 1 and eq. 4 gives
    begin{cases}
    2z-2t=0\
    x+y-z+t=2\
    3x+y+z+t=lambda\
    -2y+2z=0\
    end{cases}

    Which implies
    $$begin{cases}
    z=t\
    x=2-y\
    6-3y+3y=lambda\
    y=z=t\
    end{cases}implies lambda = 6$$






    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%2f3064819%2ffind-lambda-and-solve-the-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












      $begingroup$

      After adding of the first, second and forth equations we'll get $$3x+y+z+t=6,$$ which gives $lambda=6.$






      share|cite|improve this answer









      $endgroup$













      • $begingroup$
        But using Gauss I can't get this solution?
        $endgroup$
        – J.Doe
        Jan 7 at 10:00










      • $begingroup$
        @J.Doe Which says that there is a mistake in your computations.
        $endgroup$
        – Michael Rozenberg
        Jan 7 at 10:05
















      0












      $begingroup$

      After adding of the first, second and forth equations we'll get $$3x+y+z+t=6,$$ which gives $lambda=6.$






      share|cite|improve this answer









      $endgroup$













      • $begingroup$
        But using Gauss I can't get this solution?
        $endgroup$
        – J.Doe
        Jan 7 at 10:00










      • $begingroup$
        @J.Doe Which says that there is a mistake in your computations.
        $endgroup$
        – Michael Rozenberg
        Jan 7 at 10:05














      0












      0








      0





      $begingroup$

      After adding of the first, second and forth equations we'll get $$3x+y+z+t=6,$$ which gives $lambda=6.$






      share|cite|improve this answer









      $endgroup$



      After adding of the first, second and forth equations we'll get $$3x+y+z+t=6,$$ which gives $lambda=6.$







      share|cite|improve this answer












      share|cite|improve this answer



      share|cite|improve this answer










      answered Jan 7 at 9:45









      Michael RozenbergMichael Rozenberg

      103k1891195




      103k1891195












      • $begingroup$
        But using Gauss I can't get this solution?
        $endgroup$
        – J.Doe
        Jan 7 at 10:00










      • $begingroup$
        @J.Doe Which says that there is a mistake in your computations.
        $endgroup$
        – Michael Rozenberg
        Jan 7 at 10:05


















      • $begingroup$
        But using Gauss I can't get this solution?
        $endgroup$
        – J.Doe
        Jan 7 at 10:00










      • $begingroup$
        @J.Doe Which says that there is a mistake in your computations.
        $endgroup$
        – Michael Rozenberg
        Jan 7 at 10:05
















      $begingroup$
      But using Gauss I can't get this solution?
      $endgroup$
      – J.Doe
      Jan 7 at 10:00




      $begingroup$
      But using Gauss I can't get this solution?
      $endgroup$
      – J.Doe
      Jan 7 at 10:00












      $begingroup$
      @J.Doe Which says that there is a mistake in your computations.
      $endgroup$
      – Michael Rozenberg
      Jan 7 at 10:05




      $begingroup$
      @J.Doe Which says that there is a mistake in your computations.
      $endgroup$
      – Michael Rozenberg
      Jan 7 at 10:05











      0












      $begingroup$

      Hint: It is $$x=2-t,y=t,z=t$$ and $$lambda=6$$






      share|cite|improve this answer









      $endgroup$


















        0












        $begingroup$

        Hint: It is $$x=2-t,y=t,z=t$$ and $$lambda=6$$






        share|cite|improve this answer









        $endgroup$
















          0












          0








          0





          $begingroup$

          Hint: It is $$x=2-t,y=t,z=t$$ and $$lambda=6$$






          share|cite|improve this answer









          $endgroup$



          Hint: It is $$x=2-t,y=t,z=t$$ and $$lambda=6$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 7 at 9:59









          Dr. Sonnhard GraubnerDr. Sonnhard Graubner

          75.4k42865




          75.4k42865























              0












              $begingroup$

              Subtracting eq. 2 from both eq. 1 and eq. 4 gives
              begin{cases}
              2z-2t=0\
              x+y-z+t=2\
              3x+y+z+t=lambda\
              -2y+2z=0\
              end{cases}

              Which implies
              $$begin{cases}
              z=t\
              x=2-y\
              6-3y+3y=lambda\
              y=z=t\
              end{cases}implies lambda = 6$$






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                Subtracting eq. 2 from both eq. 1 and eq. 4 gives
                begin{cases}
                2z-2t=0\
                x+y-z+t=2\
                3x+y+z+t=lambda\
                -2y+2z=0\
                end{cases}

                Which implies
                $$begin{cases}
                z=t\
                x=2-y\
                6-3y+3y=lambda\
                y=z=t\
                end{cases}implies lambda = 6$$






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  Subtracting eq. 2 from both eq. 1 and eq. 4 gives
                  begin{cases}
                  2z-2t=0\
                  x+y-z+t=2\
                  3x+y+z+t=lambda\
                  -2y+2z=0\
                  end{cases}

                  Which implies
                  $$begin{cases}
                  z=t\
                  x=2-y\
                  6-3y+3y=lambda\
                  y=z=t\
                  end{cases}implies lambda = 6$$






                  share|cite|improve this answer









                  $endgroup$



                  Subtracting eq. 2 from both eq. 1 and eq. 4 gives
                  begin{cases}
                  2z-2t=0\
                  x+y-z+t=2\
                  3x+y+z+t=lambda\
                  -2y+2z=0\
                  end{cases}

                  Which implies
                  $$begin{cases}
                  z=t\
                  x=2-y\
                  6-3y+3y=lambda\
                  y=z=t\
                  end{cases}implies lambda = 6$$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jan 7 at 10:14









                  Lorenzo B.Lorenzo B.

                  1,8402520




                  1,8402520






























                      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%2f3064819%2ffind-lambda-and-solve-the-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

                      Human spaceflight

                      Can not write log (Is /dev/pts mounted?) - openpty in Ubuntu-on-Windows?

                      File:DeusFollowingSea.jpg