Code covered by the BSD License

# Secant iteration method

### hüseyin çilsalar (view profile)

secant iteration alorithm to find a function's root

Secant_Iteration.m
```%///Secant iteration formula////
disp(' Enter the function(Sampling Function(x^2-4*x+4))')
fx=input('f(x)= ','s');
f=inline(fx);
disp(   ' ----   Function   ---'   )
fx
%maximum value of relative difference
tolerance=input('tolerance=  ');
x0=input('1st initial value of x= ');
x1=input('2nd initial value of x= ');
x(1)=x0;
x(2)=x1;
format long e
disp(' Iterasyon No:               x               Relative difference')
for i=1:inf;
x(i+2)=(x(i)*f(x(i+1))-x(i+1)*f(x(i)))/(f(x(i+1))-f(x(i)));
a(i)=abs((x(i+1)-x(i))/(x(i)));
disp('----------------------------------------------------')
fprintf('%d    %30.16e     %25.16e\n',i,x(i),a(i))

if abs(a(i))<tolerance%Iteration stops
break
end
end
%writing to txt file
fid =fopen('Secant_Iteration.txt','w');

fprintf(fid,'\nIterasyon no:                 x:                    Relative difference:\n');
for j=1:i;

fprintf(fid,'\n%4d             %3.17e       %3.17e\n',j,x(j),a(j));
end
%plotting
ezplot(f,-90,90)
grid on
ylabel('f(x)')
text(x(i),0,'----->f(x)=0 point')

```