Newton Divided Difference Method

I'm writing a code for interpolation using Newton's method. The code works but it gave me a different value. When I enter f(x) = log(x), x0=1, it gave me y=1 which is wrong. Can anyone help me?

syms x
d = input('enter f(x)= \n')
f=inline(d);
z=diff(f(x));
f1=inline(z);
x0=input('inter x0 = \n')
x=x0
for u=0:inf
    y=x
    x=y-(f(x)/f1(x));
    if x==y
        break
    end
end

enter f(x)= 
log(x)

d =

log(x)

inter x0 = 
1

x0 =

       1

x =

       1

Warning: FOR loop index is too large. Truncating to 9223372036854775807. 

y =

       1

>>

Answer 1

[Walter Roberson]

Change the "for" to "while true"

Also, please read http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

[Akmal]

It gave me this error.

??? Maximum variable size allowed by the program is exceeded.

So I changed u=0:inf to u=0:n

And this is what I got

enter f(x)=

log(x)

d =

log(x)

enter x0 =

1

x0 =

1

x =

1

u =

0 1

y =

1