```Date: Dec 2, 2012 1:19 AM
Author: kirby urner
Subject: Re: In "square root of -1", should we say "minus 1" or "negative 1"?

On Sat, Dec 1, 2012 at 9:23 PM, Robert Hansen <bob@rsccore.com> wrote:>>> On Dec 1, 2012, at 10:39 PM, kirby urner <kirby.urner@gmail.com> wrote:>> "Did they teach anything about latitude / longitude when doing coordinate systems with ya?  No?  What school did you say that was?">>> https://www.dropbox.com/sh/hz6q14yeafltfmn/Nd3JCDzftM/Freilich-1952.pdf>> Page 105, 107>Yes, though mostly just in passing.  When we get to the XY grid andlocating points thereon, the globe is never mentioned.Coordinate geometry and geography are not strongly linked.  "Earthmeasure" is for teachers in another subject (STEM was poorlyintegrated).Related reading:http://education.nationalgeographic.com/education/encyclopedia/prime-meridian/Did you know anything about US President Chester Arthur before?  Soonafter president Garfield who did a proof of the Pythagorean theorem:http://www.pbs.org/teachers/mathline/concepts/president/activity2.shtm (web site funded by borrowings from China according to a recentpresident wannabe).The chapter emphasizes directly that positive is to the right and/orup, negative to the left and/or down (all math is ethno-math).  Page109.The idea that a number line could be a circle (diurnal time, latitudeetc.) is not explicitly discussed.When you go east (positive) how do you end up coming back from thenegative side (negative)?This relates to the issue of Int type numbers that "roll over" fromextreme positive to extreme negative.Note that reading "-5" as "minus five" and not "negative five" isexplicitly encouraged.  Page 106.There is some mention of clockwise / counterclockwise.  There's nostrong 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 samerotation from 180 opposite side, looking back, it's nowcounter-clockwise.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 athird axis does not.Space, experientially more real than planar surfaces, will have towait.  Time too (as its own dimension).Kirby
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