using fsolve to solve non-linear equations in matlab












0












$begingroup$


I'm trying to solve this system equations in matlab



syms  y z i

x=[29.6,29.4,34.4,35.1,34.3,36.1,31.6,32.9,31.5,28.3,37.1,28.4,27.3,33.1,31.3,33.1]

n = 16

eqns = sym(zeros(1, 2 * n));



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + exp(-((x(j) - y) / z));

    end

    a = i/z - a/z;

    eqns(i) = a == 0;

end



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + ((x(j) - y)/z^2) - ((x(i) - y)/z^2) * exp((-x(j) + y)/z);

    end

    a = -i/z + a;

    eqns(i + 16) = a == 0;

end

eqns

solve(eqns, [y, z])


But it seems solve can't solve this one.



Warning: Cannot find explicit solution. 

> In solve (line 316)

  In xx (line 24)


I tried to use fslove but by follow the tutorial at https://www.mathworks.com/help/optim/ug/fsolve.html?s_tid=gn_loc_drop



but when I tried to enter



function F = root2d(x)



F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);

F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;


matlab throw error.



Can someone please help me?



Thank you.



P/S: Can this problem be solved with singular?I'm trying to solve this system equations in matlab






systems-of-equations matlab singular-cas







share|cite|improve this question









$endgroup$












  • $begingroup$
    Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
    $endgroup$
    – horchler
    Mar 8 '17 at 19:59
















0












$begingroup$


I'm trying to solve this system equations in matlab



syms  y z i

x=[29.6,29.4,34.4,35.1,34.3,36.1,31.6,32.9,31.5,28.3,37.1,28.4,27.3,33.1,31.3,33.1]

n = 16

eqns = sym(zeros(1, 2 * n));



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + exp(-((x(j) - y) / z));

    end

    a = i/z - a/z;

    eqns(i) = a == 0;

end



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + ((x(j) - y)/z^2) - ((x(i) - y)/z^2) * exp((-x(j) + y)/z);

    end

    a = -i/z + a;

    eqns(i + 16) = a == 0;

end

eqns

solve(eqns, [y, z])


But it seems solve can't solve this one.



Warning: Cannot find explicit solution. 

> In solve (line 316)

  In xx (line 24)


I tried to use fslove but by follow the tutorial at https://www.mathworks.com/help/optim/ug/fsolve.html?s_tid=gn_loc_drop



but when I tried to enter



function F = root2d(x)



F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);

F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;


matlab throw error.



Can someone please help me?



Thank you.



P/S: Can this problem be solved with singular?I'm trying to solve this system equations in matlab






systems-of-equations matlab singular-cas







share|cite|improve this question









$endgroup$












  • $begingroup$
    Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
    $endgroup$
    – horchler
    Mar 8 '17 at 19:59














0












0








0





$begingroup$


I'm trying to solve this system equations in matlab



syms  y z i

x=[29.6,29.4,34.4,35.1,34.3,36.1,31.6,32.9,31.5,28.3,37.1,28.4,27.3,33.1,31.3,33.1]

n = 16

eqns = sym(zeros(1, 2 * n));



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + exp(-((x(j) - y) / z));

    end

    a = i/z - a/z;

    eqns(i) = a == 0;

end



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + ((x(j) - y)/z^2) - ((x(i) - y)/z^2) * exp((-x(j) + y)/z);

    end

    a = -i/z + a;

    eqns(i + 16) = a == 0;

end

eqns

solve(eqns, [y, z])


But it seems solve can't solve this one.



Warning: Cannot find explicit solution. 

> In solve (line 316)

  In xx (line 24)


I tried to use fslove but by follow the tutorial at https://www.mathworks.com/help/optim/ug/fsolve.html?s_tid=gn_loc_drop



but when I tried to enter



function F = root2d(x)



F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);

F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;


matlab throw error.



Can someone please help me?



Thank you.



P/S: Can this problem be solved with singular?I'm trying to solve this system equations in matlab






systems-of-equations matlab singular-cas







share|cite|improve this question









$endgroup$




I'm trying to solve this system equations in matlab



syms  y z i

x=[29.6,29.4,34.4,35.1,34.3,36.1,31.6,32.9,31.5,28.3,37.1,28.4,27.3,33.1,31.3,33.1]

n = 16

eqns = sym(zeros(1, 2 * n));



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + exp(-((x(j) - y) / z));

    end

    a = i/z - a/z;

    eqns(i) = a == 0;

end



for i = 1:n

    a = 0;

    for j = 1:i

        a = a + ((x(j) - y)/z^2) - ((x(i) - y)/z^2) * exp((-x(j) + y)/z);

    end

    a = -i/z + a;

    eqns(i + 16) = a == 0;

end

eqns

solve(eqns, [y, z])


But it seems solve can't solve this one.



Warning: Cannot find explicit solution. 

> In solve (line 316)

  In xx (line 24)


I tried to use fslove but by follow the tutorial at https://www.mathworks.com/help/optim/ug/fsolve.html?s_tid=gn_loc_drop



but when I tried to enter



function F = root2d(x)



F(1) = exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);

F(2) = x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5;


matlab throw error.



Can someone please help me?



Thank you.



P/S: Can this problem be solved with singular?I'm trying to solve this system equations in matlab






systems-of-equations matlab singular-cas




systems-of-equations matlab singular-cas






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Mar 8 '17 at 3:05









Lan Anh NguyễnLan Anh Nguyễn

11




11












  • $begingroup$
    Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
    $endgroup$
    – horchler
    Mar 8 '17 at 19:59


















  • $begingroup$
    Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
    $endgroup$
    – horchler
    Mar 8 '17 at 19:59
















$begingroup$
Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
$endgroup$
– horchler
Mar 8 '17 at 19:59




$begingroup$
Your fsolve code doesn't match the system of 32 equations you're trying to solve symbolically. It's not clear what you're trying to do. I'm also not sure why you're using i as a symbolic variable and the re-defining it in your for loops.
$endgroup$
– horchler
Mar 8 '17 at 19:59










1 Answer
1






active

oldest

votes


















0












$begingroup$

It's not clear what the problem is without being given the error, but:



F=@(x) [exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5];

x0=[1;1];

fsolve(F,x0)


worked for me. You can do this using "function F = ..." syntax, but then you need to write @F in the call to fsolve.






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%2f2176989%2fusing-fsolve-to-solve-non-linear-equations-in-matlab%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












    $begingroup$

    It's not clear what the problem is without being given the error, but:



    F=@(x) [exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5];
    
x0=[1;1];
    
fsolve(F,x0)


    worked for me. You can do this using "function F = ..." syntax, but then you need to write @F in the call to fsolve.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      It's not clear what the problem is without being given the error, but:



      F=@(x) [exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5];
      
x0=[1;1];
      
fsolve(F,x0)


      worked for me. You can do this using "function F = ..." syntax, but then you need to write @F in the call to fsolve.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        It's not clear what the problem is without being given the error, but:



        F=@(x) [exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5];
        
x0=[1;1];
        
fsolve(F,x0)


        worked for me. You can do this using "function F = ..." syntax, but then you need to write @F in the call to fsolve.






        share|cite|improve this answer









        $endgroup$



        It's not clear what the problem is without being given the error, but:



        F=@(x) [exp(-exp(-(x(1)+x(2)))) - x(2)*(1+x(1)^2);x(1)*cos(x(2)) + x(2)*sin(x(1)) - 0.5];
        
x0=[1;1];
        
fsolve(F,x0)


        worked for me. You can do this using "function F = ..." syntax, but then you need to write @F in the call to fsolve.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 8 '17 at 3:36









        IanIan

        67.6k25387




        67.6k25387






























            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%2f2176989%2fusing-fsolve-to-solve-non-linear-equations-in-matlab%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

            Quarter-circle Tiles

            Image
            up vote 0 down vote favorite I have $99$ identical square tiles, each with a quarter-circle drawn on it like this: [asy] size(1.5cm); draw(Arc((2,0),1,90,180),red+1); draw((0,0)--(2,0)--(2,2)--(0,2)--(0,0)); [/asy] When I arrange the tiles in a $9times 11$ rectangular grid, each with a random orientation, what is the expected value of the number of full circles I form? I think this problem has to do with finding the chance any given 2x2 square has a circle, but I can't find it. expected-value share | cite | improve this question asked Nov 20 at 15:03 6minecraftninja 1 2
            Read more

            build a pushdown automaton that recognizes the reverse language of a given pushdown automaton?

            Image
            0 I think it's similiar to NFAs. I replace the finite states of the given automaton for start-states for my new automaton. I do it with $epsilon$ -transition from the start state to the actual finite states of the given automaton. The start state of the given automaton will be my accepting(finite) state of my new one. All transitions will be reversed of course to recognize the reversed word. But how do I have to change the stack of the pushdown automaton? That's tricky. formal-languages automata context-free-grammar share | cite | improve this question edited Nov 29 '18 at 14:20 joee
            Read more

            Mont Emei

            Image
            Mont Emei.mw-parser-output .entete.map{background-image:url("//upload.wikimedia.org/wikipedia/commons/7/7a/Picto_infobox_map.png")} Vue du sommet Wanfo du mont Emei Géographie Altitude 3 099  m , Wanfo Coordonnées 29° 31′ 11″ nord, 103° 19′ 57″ est Administration Pays   Chine Province Sichuan Ville-préfecture Leshan Géolocalisation sur la carte : Sichuan Mont Emei Géolocalisation sur la carte : Chine Mont Emei modifier   Paysage panoramique du mont Emei, incluant le paysage panoramique du grand Bouddha de Leshan *   Patrimoine mondial de l'UNESCO Passerelle en bois sur le versant ouest Pays   Chine Subdivision Sichuan Type Mixte Critères (iv) (vi) (x) Superficie 15 400 ha Numéro d’identification 779 Zone géographique Asie et Pacifique  ** Année d’inscription 1996 (20 e session) * Descriptif officiel UNESCO ** Classification géog
            Read more