Re: roundoff in ?quadrature

["Richard W. Tarara" <rtarara@SAINTMARYS.EDU>]

----- Original Message -----
From: "John S. Denker" <jsd@MONMOUTH.COM>

> At 07:52 AM 2/1/00 -0500, Richard W. Tarara wrote:
> >  In addition [i.e. addition problems],
> > you should keep the number of decimal places of the
> > 'least' significant value.
>
> Really?  What does that imply for the following example?
>
>          4.321           4 sig digs, 3rd decimal place
>          +0.005678       4 sig digs, 6th decimal place
>        =========
>            4.326678      ?does this really have 7 dig digs?

No...you keep only 3 decimal places--4.327.  At least that is the 'rule' I
know.  Again, I do think this breaks down often in addition and subtraction,
but find the multiplication/division rules marginally useful in intro
classes.

Rick

> I'm with Leigh on this one -- thinking in terms of decimal places or sig
> digs is for amateurs.