Talk:184: Matrix Transform - Revision history

42.book.addict at 03:11, 23 February 2026

2026-02-23T03:11:54Z

136.144.42.175: comment about rotation matrices.

2026-02-22T22:46:01Z

comment about rotation matrices.

Beanie at 11:54, 18 March 2021

2021-03-18T11:54:34Z

162.158.155.170: orientation

2019-05-17T13:07:51Z

orientation

162.158.178.97 at 12:57, 16 April 2019

2019-04-16T12:57:26Z

Yomismo at 09:28, 18 March 2015

2015-03-18T09:28:13Z

108.162.218.89: Guess

2014-05-14T23:39:18Z

Guess

173.245.62.84 at 07:54, 7 April 2014

2014-04-07T07:54:48Z

Quicksilver: Created page with "This baby needs a bit more rigor. --~~~~"

2013-08-24T05:23:35Z

Created page with "This baby needs a bit more rigor. --~~~~"

New page

This baby needs a bit more rigor. --[[User:Quicksilver|Quicksilver]] ([[User talk:Quicksilver|talk]]) 05:23, 24 August 2013 (UTC)

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-RE positive or negative rotation: The rotation of the vector is 90 degrees in the NEGATIVE direction, but also notice that the matrix has the off-diagonal minus sign in the opposite place from where it would be for a positive rotation in a right-handed coordinate system. The interpretation of this is that either a) RM is using a left-handed coordinate system, instead of the typical right-handed one, or b) he took the matrix for rotating by -90 degrees and simplified by moving in the minus out of the trig functions.  Either way, the math is correct, but slightly confusing. (source: I teach CS 184)
+This baby needs a bit more rigor. --[[User:Quicksilver|Quicksilver]] ([[User talk:Quicksilver|talk]]) 05:23, 24 August 2013 (UTC)
 I think this is also a reference to the movie "The Matrix", specifically the now famous scene where Neo does 90degree back bending to dodge bullets.
 [[Special:Contributions/173.245.62.84|173.245.62.84]] 07:54, 7 April 2014 (UTC)
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 [[User:Yomismo|Yomismo]] ([[User talk:Yomismo|talk]]) 09:28, 18 March 2015 (UTC)
-IIIII'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.
+IIIII'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it. {{unsigned ip|162.158.178.97|12:57, 16 April 2019 (UTC)}}
 On clockwise/counterclockwise: I think Randall is using screen coordinates (where the top left is (0,0) and the point (1,4) is one below (1,3)), instead of standard Cartesian coordinates where the bottom left is (0,0) and going from (1,3) to (1,4) means going upwards. [[Special:Contributions/162.158.155.170|162.158.155.170]] 13:07, 17 May 2019 (UTC)

← Older revision		Revision as of 22:46, 22 February 2026
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		+	RE positive or negative rotation: The rotation of the vector is 90 degrees in the NEGATIVE direction, but also notice that the matrix has the off-diagonal minus sign in the opposite place from where it would be for a positive rotation in a right-handed coordinate system. The interpretation of this is that either a) RM is using a left-handed coordinate system, instead of the typical right-handed one, or b) he took the matrix for rotating by -90 degrees and simplified by moving in the minus out of the trig functions. Either way, the math is correct, but slightly confusing. (source: I teach CS 184)
		+
	This baby needs a bit more rigor. --[[User:Quicksilver\|Quicksilver]] ([[User talk:Quicksilver\|talk]]) 05:23, 24 August 2013 (UTC)		This baby needs a bit more rigor. --[[User:Quicksilver\|Quicksilver]] ([[User talk:Quicksilver\|talk]]) 05:23, 24 August 2013 (UTC)
	[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)		[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)

@@ Line 13: / Line 13: @@
 [[User:Yomismo|Yomismo]] ([[User talk:Yomismo|talk]]) 09:28, 18 March 2015 (UTC)
-Iiiii'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.
+IIIII'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.
 On clockwise/counterclockwise: I think Randall is using screen coordinates (where the top left is (0,0) and the point (1,4) is one below (1,3)), instead of standard Cartesian coordinates where the bottom left is (0,0) and going from (1,3) to (1,4) means going upwards. [[Special:Contributions/162.158.155.170|162.158.155.170]] 13:07, 17 May 2019 (UTC)

← Older revision		Revision as of 13:07, 17 May 2019
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	Iiiii'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.		Iiiii'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.
		+
		+	On clockwise/counterclockwise: I think Randall is using screen coordinates (where the top left is (0,0) and the point (1,4) is one below (1,3)), instead of standard Cartesian coordinates where the bottom left is (0,0) and going from (1,3) to (1,4) means going upwards. [[Special:Contributions/162.158.155.170\|162.158.155.170]] 13:07, 17 May 2019 (UTC)

← Older revision		Revision as of 12:57, 16 April 2019
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	get fun.		get fun.
	[[User:Yomismo\|Yomismo]] ([[User talk:Yomismo\|talk]]) 09:28, 18 March 2015 (UTC)		[[User:Yomismo\|Yomismo]] ([[User talk:Yomismo\|talk]]) 09:28, 18 March 2015 (UTC)
		+
		+	Iiiii'm pretty sure the "shrink" is a typo, and he meant "drink". My evidence is the xkcd book, where he just flat-out says it.

← Older revision		Revision as of 09:28, 18 March 2015
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	They'll go home (translation matrix) and shrink (scale matrix). Translation, scale and rotate are probably the most popular linear transformations.		They'll go home (translation matrix) and shrink (scale matrix). Translation, scale and rotate are probably the most popular linear transformations.
	[[Special:Contributions/108.162.218.89\|108.162.218.89]] 23:39, 14 May 2014 (UTC)		[[Special:Contributions/108.162.218.89\|108.162.218.89]] 23:39, 14 May 2014 (UTC)
		+
		+	I've been teach that the rotation was anticlockwise. Do computer turn the other way round that math teachers?
		+	by the way (left ( matrix{0 # 1 ## -1 # 0} right )*left ( binom 1 0 right)=left (binom 0 1 right) if you know what i mean.
		+	get fun.
		+	[[User:Yomismo\|Yomismo]] ([[User talk:Yomismo\|talk]]) 09:28, 18 March 2015 (UTC)

← Older revision		Revision as of 23:39, 14 May 2014
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	I think this is also a reference to the movie "The Matrix", specifically the now famous scene where Neo does 90degree back bending to dodge bullets.		I think this is also a reference to the movie "The Matrix", specifically the now famous scene where Neo does 90degree back bending to dodge bullets.
	[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)		[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)
		+
		+	Maybe another reference:
		+	They'll go home (translation matrix) and shrink (scale matrix). Translation, scale and rotate are probably the most popular linear transformations.
		+	[[Special:Contributions/108.162.218.89\|108.162.218.89]] 23:39, 14 May 2014 (UTC)

← Older revision		Revision as of 07:54, 7 April 2014
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	This baby needs a bit more rigor. --[[User:Quicksilver\|Quicksilver]] ([[User talk:Quicksilver\|talk]]) 05:23, 24 August 2013 (UTC)		This baby needs a bit more rigor. --[[User:Quicksilver\|Quicksilver]] ([[User talk:Quicksilver\|talk]]) 05:23, 24 August 2013 (UTC)
		+	[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)
		+	I think this is also a reference to the movie "The Matrix", specifically the now famous scene where Neo does 90degree back bending to dodge bullets.
		+	[[Special:Contributions/173.245.62.84\|173.245.62.84]] 07:54, 7 April 2014 (UTC)