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Topic: One or two arrows on a coordinate axis?
Replies: 21   Last Post: Jan 26, 2012 12:53 PM

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 DCJLEE@AOL.COM Posts: 28 Registered: 12/6/04
One or two arrows on a coordinate axis?
Posted: Jan 19, 2012 8:28 PM
 att1.html (2.4 K)

I've always thought that a cartesian coordinate axis consists of
(1) a straight line with a distinguished point representing 0,
(2) an orientation, indicated by an arrow, that indicates the
direction of increasing coordinate values, and
(3) a unit, representing 1, located away from 0 on the side
of the arrow:
0 1
-----------------------------------|---------|------------------------------
------>

Recently, in discussions with fellow instructors at a Ph.D.
granting university, I became aware that there are actually
two "camps" regarding this issue:
(I) One arrow on each axis, as described above, and
(II) Two arrows on each axis (presumably to indicate that
the axis is supposed to be extended indefinitely at both ends),

0 1
<-----------------------------------|---------|-----------------------------
------->

as exemplified by this statement:
>>>
It's not anything that I've ever thought about before, but I'd probably
consider myself in the "double-arrow camp" on the axes.
>>>

Any comment or clarification on this matter will be much appreciated.

John Lee

Date Subject Author
1/19/12 DCJLEE@AOL.COM
1/19/12 Guy Brandenburg
1/20/12 Alain Schremmer
1/20/12 Clyde Greeno @ MALEI
1/20/12 Alain Schremmer
1/21/12 Phil Mahler
1/21/12 Alain Schremmer
1/22/12 Laura Bracken
1/22/12 Alain Schremmer
1/22/12 RotmanJ
1/22/12 Clyde Greeno @ MALEI
1/22/12 Alain Schremmer
1/23/12 Wayne Mackey
1/24/12 RotmanJ
1/24/12 Alain Schremmer
1/26/12 Wayne Mackey
1/20/12 Wayne Mackey
1/21/12 Alain Schremmer
1/21/12 Clyde Greeno
1/21/12 Alain Schremmer
1/21/12 Phil Mahler
1/21/12 Alain Schremmer