1. May 30, 2010

### muso07

1. The problem statement, all variables and given/known data
Use the method of undetermined coefficients to derive the fourth-order Adams-Moulton formula
xk+1=xk+ (h/24)(9fk+1+19fk-5fk-1+fk-2

2. Relevant equations
Adams-Moulton: $$x_{k+1}=x_{k}+h\Sigma ^{n}_{i=0}\beta_{i}f_{k+1-i}$$

3. The attempt at a solution
It has to be exact for x(t)=1, x(t)=t, x(t)=t2, x(t)=t3

So I have to solve for the coefficients of $$x_{k+1}=x_{k}+h(\beta_{0}f_{k+1} + \beta_{1}f_{k} + \beta_{2}f_{k-1} + \beta_{3}f_{k-2})$$

I know I need to set up a system of equations, but I'm confused as to what fk is.. Is it just the derivative of xk?

edit: Nevermind, I figured it out. :)

Last edited: May 30, 2010