# How to show the iterations and the answers and the graph

2 views (last 30 days)
Dean Yankee Jabili on 3 May 2021
Answered: David Hill on 3 May 2021
clc
clear
m = 68.1;
g = 9.81;
t = 10;
v = 40;
f =@(c) (g*m*(1-(exp((-c*t)/m)))/c)-v;
N = 100; %iterations
err = 0.1;
c = 0.1:0.1:50;
x1 = c(1);
xu = c(end);
%root check
S = f(x1)*f(xu);
if S > 0
error('No root');
else
for i = 1:N
xr = xu - (f(xu)*(x1-xu))/(f(x1)-f(xu));
S = f(xr)*f(xu);
if S < 0
x1 = xr;
xr = xu - (f(xu)*(x1-xu))/(f(x1)-f(xu));
Err = abs(xr - x1);
if Err < err
break;
end
else if S > 0
xu = xr;
xr = xu - (f(xu)*(x1-xu))/(f(x1)-f(xu));
Err = abs(xr - xu);
if Err < err
break;
end
else
break;
end
ii = i;
end
end
end
disp(['The Root is: ' num2str(xr) ',with accuracy: ' num2str(Err) ', NO Iteration:' num2str(ii)]);
this is my finished code and how do i display the loop of this function? and also the display of the graph

David Hill on 3 May 2021
Why not use a while loop?
m = 68.1;
g = 9.81;
t = 10;
v = 40;
f =@(c) (g*m*(1-(exp((-c*t)/m)))/c)-v;
err = 1e-10;
c = 0.1:0.1:50;
x1 = c(1);
xu = c(end);
%root check
S = f(x1)*f(xu);
if S > 0
error('No root');
else
Err=1;
count=1;
while Err>err
xr(count) = xu - (f(xu)*(x1-xu))/(f(x1)-f(xu));
S = f(xr(count))*f(xu);
if S < 0
Err = abs(xr(count) - x1);
x1 = xr(count);
else
Err = abs(xr(count) - xu);
xu = xr(count);
end
count=count+1;
end
disp(['The Root is: ' num2str(xr(count-1)) ',with accuracy: ' num2str(Err)...
', NO Iteration:' num2str(count-1)]);
plot(1:count-1,xr)%this plots iterations vs. xr
end