Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down on April 23, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Why the square of a negative number is still negative


From   Austin Nichols <austinnichols@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Why the square of a negative number is still negative
Date   Fri, 16 Dec 2011 11:37:19 -0500

Tiago V. Pereira <tiago.pereira@mbe.bio.br>:
Just order of operations; `x'^2 or -2^2 is the negative of 2 squared
or -4, and if you want (-2)^2 you have to wrap your local in
parentheses.

On Fri, Dec 16, 2011 at 11:31 AM, Tiago V. Pereira
<tiago.pereira@mbe.bio.br> wrote:
> Dear statalisters,
>
> Can someone explain why is this happening?:
>
> local x = -2
> */Approach A:
> dis (`x'^2)*(5)
> */Approach B:
> dis (`x'*`x')*(5)
> */Approach C:
>  dis ((`x')^2)*(5)
>
>
> My output is:
>
> . dis (`x'^2)*(5)
> -20
>
> . */Approach B:
>
> . dis (`x'*`x')*(5)
> 20
>
> . */Approach C:
>
> .  dis ((`x')^2)*(5)
> 20
>
>
> Do I need vacations? (Am I forgetting something very simple from
> mathematics?)
>
> All the best,
>
> Tiago

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index