The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Education » math-teach

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: In "square root of -1", should we say "minus 1" or "negative 1"?
Replies: 5   Last Post: Dec 3, 2012 12:53 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
kirby urner

Posts: 3,690
Registered: 11/29/05
Re: In "square root of -1", should we say "minus 1" or "negative 1"?
Posted: Dec 2, 2012 1:19 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Sat, Dec 1, 2012 at 9:23 PM, Robert Hansen <> wrote:
> On Dec 1, 2012, at 10:39 PM, kirby urner <> wrote:
> "Did they teach anything about latitude / longitude when doing coordinate systems with ya? No? What school did you say that was?"
> Page 105, 107

Yes, though mostly just in passing. When we get to the XY grid and
locating points thereon, the globe is never mentioned.

Coordinate geometry and geography are not strongly linked. "Earth
measure" is for teachers in another subject (STEM was poorly

Related reading:

Did you know anything about US President Chester Arthur before? Soon
after president Garfield who did a proof of the Pythagorean theorem:
(web site funded by borrowings from China according to a recent
president wannabe).

The chapter emphasizes directly that positive is to the right and/or
up, negative to the left and/or down (all math is ethno-math). Page

The idea that a number line could be a circle (diurnal time, latitude
etc.) is not explicitly discussed.

When you go east (positive) how do you end up coming back from the
negative side (negative)?

This relates to the issue of Int type numbers that "roll over" from
extreme positive to extreme negative.

Note that reading "-5" as "minus five" and not "negative five" is
explicitly encouraged. Page 106.

There is some mention of clockwise / counterclockwise. There's no
strong initiative to develop handedness as a concept.

There's no mention of an observer or observer position.

Clockwise is relative to an observer. If you look at the same
rotation from 180 opposite side, looking back, it's now

Having directionality depend on the observer is not discussed.
Schoolish math of the 1900s tends to ignore the observer.

No turtle graphics yet :-)

The second number line and a flat grid comes within the chapter, but a
third axis does not.

Space, experientially more real than planar surfaces, will have to
wait. Time too (as its own dimension).


Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.