PDA

View Full Version : Newton's Method


DeadxBunny
Apr30-07, 02:11 AM
1. The problem statement, all variables and given/known data
Identify the formula

xn+1 = -2xn + 3yxn^(2/3)

as the Newton's method for a certain function. Here y is a fixed constant. What is the limit of xn?


2. Relevant equations
Newton's method?:

xn+1 = xn - f(xn)/f'(xn)


3. The attempt at a solution
I don't know how to begin.

Thanks in advance!

christianjb
Apr30-07, 03:40 AM
1st step- Newton's method gives

x_n-x_{n-1}=f(x_n)/f'(x_n)

So rearrange your equation to get f(x_n)/f'(x_n). Then think.