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


From   Richard Williams <richardwilliams.ndu@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 11:47:34 -0500

See http://www.stata.com/support/faqs/lang/macpow.html. If you are not careful, what you intend to be seen as a negative sign is instead being interpreted as a minus sign.

At 11:31 AM 12/16/2011, Tiago V. Pereira 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


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Richard Williams, Notre Dame Dept of Sociology
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