# Math Help - need help! using newton's method

1. ## need help! using newton's method

need help....

2. Hi,

I assume that you know Newton's rule.
$x_{n+1}=x_{n}-\frac{f(x_n)}{f'(x_n)}$

With your function this formula becomes:

$x_{n+1}=x_{n}-\frac{x_n^3-x_n^2-1}{3x_n^2-2x_n}$

Now $x_1 = 1$. Thus

$x_{2}=1-\frac{1-1-1}{3-2}= 2$

$x_{3}=2-\frac{8-4-1}{12-4}= 1.625$

...

$x_{7}\approx 1.465571232$

EB

3. Hi, it's me again. I've modified your image so you can see the first steps how the value is calculated by Newton's method. The red and blue lines are tangents.