MATLAB: Plot in Bisection Method

bisection plot

%% Bisection Method
% f(x) = 2sin(x) + 2cos(x)
a = -1;
b = 1;
tol = 10^-3;
iter = 0;
fprintf('iter \t    a     \t       b      \t      fark\n' );
fprintf('---------------------------------------------\n' );
while (abs(a-b)>tol)
    fa = 2*sin(a) + 2*cos(a);
    fb = 2*sin(b) + 2*cos(b);
    m = (a+b)/2;
    fm = 2*sin(m) + 2*cos(m);
    if (fa*fm<0)
        b=m;
    else
        a=m;
    end
    iter = iter + 1 ;
    fprintf('%d \t %f \f \t %f \t %f \t %f\n',iter,a,b, abs(a-b),tol);
end
Hey everyone
How can I plot this code with functions showing the location of the
initial guess and the approximated root value?

Best Answer

Utku - I suppose that you would want to plot the m that is generated on each iteration of the loop. If that is the case, you could save that data to an array and plot that array when you exit the loop like
iter = 1;
mData = []; % create an array
while (abs(a-b)>tol)
    fa = 2*sin(a) + 2*cos(a);
    fb = 2*sin(b) + 2*cos(b);
    m = (a+b)/2;
    fm = 2*sin(m) + 2*cos(m);
    if (fa*fm<0)
        b=m;
    else
        a=m;
    end
    mData[iter] = m; % save data to array
    iter = iter + 1 ;
    fprintf('%d \t %f \f \t %f \t %f \t %f\n',iter,a,b, abs(a-b),tol);
end
plot(mData); % plot data
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