MATLAB: How to join all points in the plot.

plot

hello everyone, kindly help me to how to join all points with line.. here is my code.
function bisection
func=@(n) 40*n^1.5-875*n+35000;
maxit=50;
es=0.0001;
xl=50;
xu=100;
test = func(xl)*func(xu);
if test>0,error('no sign change'),end
mp = linspace(xl,xu);
fp = 40*mp.^1.5-875*mp+35000;
iter = 0; xr = xl; ea = 100;
fprintf('at iteration %2i\nxl = %2i\nxu = %2i\n ', 0, xl,xu)
fprintf('    iteration        xl        xu        xr        f(x)        ea')
while (1)
% plot(iter,ea,'-*');axis ([0 20 -5 16])
xrold = xr;
xr = (xl + xu)/2;
hold on
plot(iter,ea,'r.-','markersize',20); axis([0 20 -5 40])
iter = iter + 1;
if xr ~= 0,ea = abs((xr - xrold)/xr) * 100;end
test = func(xl)*func(xr);
if test < 0
xu = xr;
elseif test > 0
xl = xr;
else
ea = 0;
end
if ea <= es | iter >= maxit,break,end
   fprintf('\n%10i %14.4f %10.4f %10.3f %10.3f %9.3f', iter,xl,xu,xr,func(xr),ea)
end    
fprintf('\n\nRoot is %7.3f after %2i iterations. \n\n', xr, iter)
root = xr; fx = func(xr);
fprintf('\nerror is = %17f\ntrue root=%17.4f\niteretions taken= %10.4f\n F(n)=%20.4f\n',ea,xr,iter,func(xr));
end

Best Answer

First, remove the plot call from the loop.
Second, create vectors for ‘ea’ and ‘iter’.
Third, plot the vectors after the loop:
while (1)
% plot(iter,ea,'-*');axis ([0 20 -5 16])
xrold = xr;
xr = (xl + xu)/2;
%  hold on
% plot(iter,ea,'r.-','markersize',20); axis([0 20 -5 40])
iter = iter + 1;
if xr ~= 0
    ea = abs((xr - xrold)/xr) * 100;
end
test = func(xl)*func(xr);
if test < 0
    xu = xr;
elseif test > 0
    xl = xr;
else
    ea = 0;
end
eav(iter) = ea;                                         % Vector: ‘ea’
iterv(iter) = iter;                                     % Vector: ‘iter’
if ea <= es | iter >= maxit,break,end
       fprintf('\n%10i %14.4f %10.4f %10.3f %10.3f %9.3f', iter,xl,xu,xr,func(xr),ea)
end
and:
figure(1)
plot(iterv,eav,'r.-','markersize',20); 
axis([0 20 -5 40])
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