# (Methods)Parameters v Undetermined Coefficients

1. Apr 30, 2008

### hils0005

[SOLVED] (Methods)Parameters v Undetermined Coefficients

Can anyone tell me why I would use one technique over the other? It seems as though undetermined Coef. is much easier to do but I suppose that comes with limitations???

2. Apr 30, 2008

### rock.freak667

Well if you can guess the particular integral of a Diff eq'n then method of undetermined coefficients will work and the pi's you can usually guess are usually $e^{ax},sinax,cosax,sinax+cosax,etc.$. But if you have tanx or $\frac{1}{1+x}$ then you'll need to use variation of parameters to solve.

3. Apr 30, 2008

### hils0005

Thanks for the explanation