Newton's Method

[Riogho]

I'm using Newton's method to find the zero for this problem

 

[math]

\left( x^3 + 2x^2 - 4)^{\frac{1}{3}}

[/math]

 

Meh, I can't use latex.

 

The Cube root of X^3 + 2x^2 - 4

 

Anyways, I've ran it through a few times with my initial guess being 1.

 

The first itme I ran it through i got 2 as my answer, and then the second time my answer jumped over the actual root (which is 1.18 or something) to be .28942.... i checked my work and it's correct.

 

Why would it do that?

[D H]

Check your work again. Starting with an initial guess of 1, with Newton's method you should get the sequence 1, 1.125, 1.1230, 1.1303, 1.1304, ...