## Search found 102 matches

Tue Jun 07, 2011 5:30 pm UTC
Forum: Mathematics
Topic: Proof that there are at least 5 regular polyhedra?
Replies: 11
Views: 3206

### Re: Proof that there are at least 5 regular polyhedra?

Generally, we are not interested in non-constructive existence proofs when constructive ones are available. Counterexamples to this maxim are usually situations where a single general existence proof covers a large number of objects requiring many different constructions. In this case it really only...
Wed Jan 12, 2011 5:27 pm UTC
Forum: Mathematics
Topic: Example of a student learning*
Replies: 15
Views: 2418

### Re: Example of a student learning*

For the record, I specifically instructed them not to simplify at all. The item was testing student knowledge of the definition of trigonometric ratios in the context of right triangles. In addition to making grading easier, this reduced the number of factors affecting the score for the item.
Thu Jan 06, 2011 10:20 pm UTC
Forum: Mathematics
Topic: Four even spaced points on a sphere?
Replies: 11
Views: 3704

### Re: Four even spaced points on a sphere?

One can also use basic right triangle trigonometry without resorting to "fancy linear algebra". Consider regular tetrahedron ABCD , with center at point O . Let M be the midpoint of the segment AB . Since AO=BO , \angle AOM is congruent to \angle MOB, and OM is perpendicular to AB . It is ...
Thu Jan 06, 2011 8:46 pm UTC
Forum: Mathematics
Topic: Example of a student learning*
Replies: 15
Views: 2418

### Example of a student learning*

On a recent exam, I asked a question with the answer \frac{\sqrt{3}+1}{\sqrt{3}-1}. Several students, including some with otherwise correct answers, made the mistake of either writing \sqrt{3+1} and \sqrt{3-1} or, very ambiguously, \sqrt{3+}1 and \sqrt{3-}1 . On the papers that exhibited this error,...
Wed Jan 05, 2011 5:54 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0843: "Misconceptions"
Replies: 186
Views: 42108

### Re: 843: "Misconceptions"

First Tuesday in Febuary: The earliest day for primaries in the 2012 election. Thats all I could find. My guess is that is a a date far enough in the future that we have time to make this a reality beginning this year. I say we do this in all grade 6+. Set aside this day in your lesson planning to f...
Tue Jan 04, 2011 5:01 pm UTC
Forum: Language/Linguistics
Topic: "Since then, and up to date"
Replies: 12
Views: 5284

### Re: "Since then, and up to date"

This construction seems wrong to me. First, "up-to-date" or "up to date" is generally used as an adjective, not a preposition. Example: "This list of examples is up-to-date." The related prepositional phrase is "to date". Example: "To date only forty-thre...
Mon Jan 03, 2011 9:09 pm UTC
Forum: Mathematics
Topic: ln(x) or log(x)?
Replies: 63
Views: 9363

### Re: ln(x) or log(x)?

It doesn't really matter with ln/log, but with degrees/radians, it is often better to use degrees in non-math-related contexts because they're better for actually measuring, which is KIND OF important for applying our math to real world situations. It's "nice" in that context to have a fu...
Mon Jan 03, 2011 8:50 pm UTC
Forum: Mathematics
Topic: A little conundrum with infinity
Replies: 9
Views: 1687

### Re: A little conundrum with infinity

Ah! Buffon! Excellent. Lets make the inital velocity fixed so that the length of the balls path is fixed. Now we are considering a random segment in the plane. (A0gain, we need to have a probability distribution for that to be meaningful.) Now to be really interesting, lets change the question to: w...
Tue Dec 07, 2010 8:52 pm UTC
Forum: Language/Linguistics
Topic: Do you use the term "Ginger"?
Replies: 65
Views: 20569

### Re: Do you use the term "Ginger"?

Thanks to the Doctor and South Park, I am quite familiar with the term, and I have heard people use it. However, I haven't heard an Americans using it as their usual term. Apart from the connotations is has from elsewhere, I like the sound of it. It does bother me a little though, since ginger root ...
Wed Nov 17, 2010 7:47 pm UTC
Forum: Mathematics
Topic: Tips for how to study undergrad math the right way?
Replies: 32
Views: 3949

### Re: Tips for how to study undergrad math the right way?

What a nice discussion I've started! My comment was meant as a purely pragmatic suggestion. My experience talking with graduate students and faculty from various schools is that every PhD program (and most MA only programs as well, although I have less info on them) either REQUIRE students to study ...
Tue Nov 16, 2010 8:38 pm UTC
Forum: Mathematics
Topic: Tips for how to study undergrad math the right way?
Replies: 32
Views: 3949

### Re: Tips for how to study undergrad math the right way?

On a related topic, if you are planning to do graduate work in mathematics, then your choice of courses is probably just as important as your performance in your math classes. (If not for admission, then certainly for being successful once you get in!) Some of theses are probably required for a majo...
Tue Nov 16, 2010 5:51 pm UTC
Forum: Mathematics
Topic: Tips for how to study undergrad math the right way?
Replies: 32
Views: 3949

### Re: Tips for how to study undergrad math the right way?

Learn how to read a math. This is not intended to sound demeaning or condescending. Reading mathematics is very different from reading literature or anthropology or chemistry. It is dense . My casual reading speed is probably around 400-450wpm. Thats how I read novels, news articles, &c. That tr...
Tue Nov 16, 2010 4:29 pm UTC
Forum: Language/Linguistics
Topic: The Ampersand Appreciation Society
Replies: 47
Views: 8817

### Re: The Ampersand Appreciation Society

Sadly, I never developed a handwritten ampersand. However, I have been making an effort to abreviate et cetera as &c in my everyday typing. I find it pleasingly appropriate and it prevents me from making the the irritating mistake of "ect". In my experience, Americans are for more like...
Tue Nov 02, 2010 8:23 pm UTC
Forum: Language/Linguistics
Topic: Words which are different depending on the profession
Replies: 16
Views: 2904

### Re: Words which are different depending on the profession

Yeah, words used in a profession often have different meanings. Sometimes even in the same profession. "Normal" has probably dozens of technical meanings in mathematics. They all mean very different things. The "linear functions" (degree one polynomial, graph is a line) one studi...
Tue Nov 02, 2010 7:54 pm UTC
Forum: Mathematics
Topic: Origami Equilateral Triangle
Replies: 5
Views: 2191

### Re: Origami Equilateral Triangle

In case that previous comment wasn't clear: It IS possible to trisect angles with paper-folding. Paper-folding is a more powerful construction method than compass and straightedge. Any point that can be found with compass and straightedge can be found by paper-folding, but there are points that can ...
Tue Nov 02, 2010 6:49 pm UTC
Forum: Language/Linguistics
Topic: A regional use of prepositions
Replies: 16
Views: 3722

### Re: A regional use of prepositions

I am confident that I am hearing "on the hallway". If it is evolved from "in the hallway", then it has diverged noticeably from other uses of in. It is still "in your mailbox" in "in the classroom". Eventually I'll ask somebody about it, but so far the most no...
Fri Oct 29, 2010 1:56 pm UTC
Forum: Language/Linguistics
Topic: A regional use of prepositions
Replies: 16
Views: 3722

### Re: A regional use of prepositions

I'm in Kinston, NC. I don't believe I have heard any locals say "in the hallway" yet. Hm... I suppose people will say "get off (of) the hallway" here too, instead of "get out (of) the hallway". I don't think I've heard that yet. (Teachers usually just say "get to c...
Fri Oct 29, 2010 1:52 pm UTC
Forum: Language/Linguistics
Topic: "You want I should"
Replies: 35
Views: 23750

### Re: "You want I should"

Of course I found other Yiddishisms, which were interesting even though they did not show up very much. For example the much-used and -loved “should,” as in “they want we should go on the march.” This is called the subjunctive case in Latin and Spanish, where it has a different conjugation. In Yidd...
Thu Oct 28, 2010 11:45 am UTC
Forum: Language/Linguistics
Topic: PetsMart and ClimbMax
Replies: 9
Views: 5088

### Re: PetsMart and ClimbMax

AdvancED a school accreditation company. Although this one just annoys me.
Wed Oct 27, 2010 4:06 pm UTC
Forum: Language/Linguistics
Topic: A regional use of prepositions
Replies: 16
Views: 3722

### Re: A regional use of prepositions

I guess it's safe to reveal that I am an "in" person, and that the locals here are one of the other two. Has anyone heard "on the hallway" or "at the hallway"? Also: good to hear from NC. That means that this odd language is not universal through the state. (I'm in Nort...
Tue Oct 26, 2010 8:47 pm UTC
Forum: Language/Linguistics
Topic: A regional use of prepositions
Replies: 16
Views: 3722

### A regional use of prepositions

I have recently moved to a new town where I am teaching high school. I have noticed that faculty here seem to universally use a certain pronoun with "the hallway" which is different from the preposition I have always heard and used in the previous four communities (in two states) where I h...
Tue Oct 26, 2010 8:01 pm UTC
Forum: Language/Linguistics
Topic: Does this argument have a name?
Replies: 8
Views: 2679

### Re: Does this argument have a name?

What they don't know won't hurt them.
Wed Oct 06, 2010 4:23 pm UTC
Forum: Mathematics
Topic: Sufficiently large values of 2 such that 2+2=5
Replies: 5
Views: 2954

### Re: Sufficiently large values of 2 such that 2+2=5

The main error here is that " 2+2=5 " (meaning there are three points p,q,r so that d(p,q)=2, d(q,r)=2 , but d(p,r)=5 ) violates the Triangle Inequality. The Triangle Inequality is part of the definition of a metric. A Metric defines what distance means for a space....
Fri Feb 26, 2010 2:01 am UTC
Forum: Language/Linguistics
Topic: Think Before Naming Your Child
Replies: 1622
Views: 352419

### Re: Think Before Naming Your Child

Re: Istari/Istari as a name

The English equivalent of Istar is, of course, "wizard". But Sophia is a perfectly good girls name with essentially the same meaning.

Or... Ishtar. Also a feminine name, although hardly less strange than Istar would be. Rather different meaning though.
Fri Feb 26, 2010 1:49 am UTC
Forum: Language/Linguistics
Topic: Words you think English should have or bring back.
Replies: 643
Views: 174838

### Re: Words you think English should have or bring back.

::smirk:: Those are commonly called "commonly confused words"

Synophone is a French word meaning the same as our word synonym, but I have found it used in some English settings to mean something like what you intend. It seems to come up most often in language learning settings.
Sun Aug 09, 2009 2:21 am UTC
Forum: Mathematics
Topic: Magnets and polyhedra
Replies: 15
Views: 6378

### Re: Magnets and polyhedra

I enjoy making tetrahedral complexes.

Also, I'm jealous of your toys. I just borrow an officemate's magnetix.
Sat Aug 08, 2009 6:11 pm UTC
Forum: Language/Linguistics
Topic: "off of"
Replies: 80
Views: 13346

### Re: "off of"

Apparently the length of my previous post caused people to miss the point at the very beginning. The use of "off of" is the older form which is becoming obsolete and replaced by "off". If this theory is true, then "off of" is not a "American bastardization of Engli...
Sat Jul 18, 2009 9:25 pm UTC
Forum: News & Articles
Topic: Kindle Books Repossesed
Replies: 42
Views: 3744

### Re: Kindle Books Repossesed

Right, but only if Barnes and Noble had printed their own, unauthorized, copies of the books and had burned them once they retrieved them.
Sat Jul 18, 2009 5:48 am UTC
Forum: Mathematics
Topic: Graphing X^X
Replies: 13
Views: 2331

### Re: Graphing X^X

$x^x = e^{x\ln(x)}$
But [imath]\ln(x)[/imath] is not well defined for [imath]x\leq0[/imath]. One can define exponentials in a complex analytic setting, but the is no unique choice of definition. You can look it up any intro. complex analysis text.
Sat Jul 18, 2009 5:32 am UTC
Forum: Language/Linguistics
Topic: The Line Between Improvement and Degradation
Replies: 47
Views: 5485

### Re: The Line Between Improvement and Degradation

Yeah... I don't actually have examples. (I do think that there are cases where many people are not certain whether literally is being used literally or hyperbolically.)

And I meant large-scale as in large numbers of people involved, not as in large problems.
Fri Jul 17, 2009 7:23 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0541: "TED Talk"
Replies: 221
Views: 53250

### Re: "TED Talk" Discussion

Fri Jul 17, 2009 8:50 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0541: "TED Talk"
Replies: 221
Views: 53250

### Re: "TED Talk" Discussion

Fri Jul 17, 2009 8:42 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0611: "Disaster Voyeurism"
Replies: 105
Views: 29251

### Re: "Disaster Voyeurism" Discussion

Whenever I see pictures of houses perched at the edge of steep receding ocean shore or along an obvious fault line, especially if it is a big expensive looking house, I always root for the house to loose the battle. Why shouldn't your house fall into the ocean? Your the idiot that decided he just ha...
Fri Jul 17, 2009 6:11 am UTC
Forum: School
Topic: What do other countries teach about The united states?
Replies: 78
Views: 9672

### Re: What do other countries teach about The united states?

My schooling was in Ohio. Our history classes pretty much ignored Canada after the war of 1812 (although I barely remember learning anything about that). What bothered me was how little we learned about the UK. Sure, we learned about it during Exploration, Colonialism, the America Revolution, Indust...
Fri Jul 17, 2009 3:58 am UTC
Forum: General
Topic: xkcd-worthy life
Replies: 15
Views: 1736

### Re: xkcd-worthy life

@krazykate Brilliant idea! I'll get right on learning Chinese. ::evil laugh:: Also, I'll need to buy a black pork pie hat.

Also, props on the cat thing!
Thu Jul 16, 2009 8:22 pm UTC
Forum: General
Topic: What type of hat does the black hat guy wear?
Replies: 25
Views: 5862

### Re: What type of hat does the black hat guy wear?

Wow. Wearing a black, pork pie shaped TARDIS is the ultimate in both fashion and convenience.
Thu Jul 16, 2009 8:17 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 0608: "Form"
Replies: 94
Views: 28608

### Re: "Form" discussion

This reply intentionally devoid of meaning.
Mon Jul 13, 2009 5:55 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0609: "Tab Explosion"
Replies: 176
Views: 56840

### Re: "Tab Explosion" Discussion

I just lost this afternoon to TvTropes. Because of a link from an xkcd thread. Now Randall is mocking me for it...
Mon Jul 13, 2009 2:06 am UTC
Forum: General
Topic: What type of hat does the black hat guy wear?
Replies: 25
Views: 5862

### Re: What type of hat does the black hat guy wear?

I actually clicked on that expecting a hat. Shame on me.
Mon Jul 13, 2009 2:01 am UTC
Forum: General
Topic: xkcd-worthy life
Replies: 15
Views: 1736

### Re: xkcd-worthy life

How about calculating your "Google Dominance Quotient"? I did a search for my username and... GDQ = \frac{\# \hbox{ results about me}}{\#\hbox{ results}}=62\%. This is how I discovered that there is one other person, on the other side of the planet that has started using the same handle. T...

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