I must write a program with bisection methot which has initial guesses as xl=0 xu=3. The iterations must end when | Ea | < 10^(-3) . xr represent the current root. I must plot | Ea | versus i and also f(xr) versus i.
Also my output must be print the i , xl , xu, f(xl), f(xu), xr, f(xr), | Ea | in each iteration.
I try to do plotting but when I run my code there is:
Error using plot
Vectors must be the same length.
NOTE: I want to plot with using set because I think it is easier to understand for me.
THANKS..
clc
clear all
close all
f=@(x) x^3 - x - 3;
serr=[]
sf=[]
xl=0;
xu=3;
xr1=100;
error=100;
tolerance=1e-03;
fl=f(xl);
fu=f(xu);
fr = f(xr1);
m=1;
display('BISECTION METHOD')
display('---------------------')
fprintf('%10s %10s %10s %10s %10s %10s %10s %10s\n','m','xl','xu','f(xl)','f(xu)','f(xl)','f(xu)','|Ea|')
for i=1:1:1
fprintf('%2.0f %12.5f %12.5f %12.5f %12.5f %12.5f %12.5f %12.5f\n', m, xl, xu,f(xl),f(xu), xr1,f(xr1), error)
while error>tolerance
xr2 = (xu+xl)/2;
fr=f(xr2);
if sign(fr)==sign(fl)
xl = xr2;
fl = fr;
else
xu = xr2;
fu = fr;
xr1=xr2;
xr2 = (xl+xu)/2;
end
error = abs(xr2-xr1)/xr2*100;
serr=[serr error];
sf=[sf f(xr2)];
m = m+1;
fprintf('%2.0f %12.5f %12.5f %12.5f %12.5f %12.5f %12.5f %12.5f\n', m, xl, xu,f(xl),f(xu), xr2,f(xr2), error)
end
end
subplot(1,2,1)
plot(1:m,serr,'-o')
xlabel(' i')
ylabel ('error')
subplot(1,2,2)
plot(1:m,sf,'-o')
xlabel(' i')
ylabel ('f(xr)')
