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Matlab Displaying the Fit Equation On graph.

  1. Apr 2, 2017 #1
    I have a lineer data and I want to write the equation of it on the graph.
    The x axis is inverse distance (1/m) and I showed as "d"
    The y axis is capacitance (C) and I showed it like "C"
    My data name is d_C

    Here my codes that I used for now
    >> d=d_C(:,1);
    >> C=d_C(:,2);
    >> plot(d,C,'go');
    >> hold on
    >> xlabel('Inverse Distance (1/m)','Fontsize',21)
    >> ylabel('Capacitance (C)','Fontsize',21)
    >> title('Inverse Distance vs Capacitance,Part (A)','Fontsize',23)
    >> grid on
    >> p = polyfit(d,C,1)

    p =

    0.0003 0.0414

    >> Cfit=polyval(p,d);
    >> plot(d,Cfit,'-b');
    >> h = legend('Data','Best fit','Location','southeast');
    >> set(h,'Fontsize',20);

    I just need to write the equation on the graph like probably y=0.0003x+0.0414 (I am not sure about this though).I need codes.I cant do it on manually

    Any help would be great

    Attached Files:

    Last edited: Apr 2, 2017
  2. jcsd
  3. Apr 2, 2017 #2


    User Avatar
    Gold Member

    From a MATLAB newsgroup post:

    a = p(1)
    b = p(2)
    polyfit_str = ['y = ' num2str(a) ' *x + ' num2str(b)]
    % polyfit_str will be : y = 4*x + 2
  4. Apr 2, 2017 #3
    Thanks a lot.I did it
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