med_cat: (SH education never ends)
[personal profile] med_cat
Today's word is brought to you by [personal profile] prettygoodword , who posted this back on March 6th:

rhombicosidodecahedron - n., an Archimedean solid with 62 regular faces (20 triangles, 30 squares, and 12 pentagons).



Thanks, WikiMedia!

Okay, so it's probably just as much cheating to pull brobdingnagian words from solid geometry as it is from chemistry, but I just love this one -- so fun to say, and so fun to look at. Technically, there are two solids called a rhombicosidodecahedron, of which this is the small rhombicosidodecahedron -- the great rhombicosidodecahedron also has 62 faces, but with 30 squares, 20 hexagons, and 12 decagons. I'm not going to parse out the elements -- er, um, I mean, doing so is left as an exercise for the reader. But I will mention that the name was coined in Latin by Johannes Kepler (in The Harmony of the World, 1619).

---L.
~~~

This made me recall Marianne Moore's poem "The Icosasphere", which you can find, along with mathematical commentary, at the Poetry and Mathematics blog here

And you can read more about the icosahedron, the dodecahedron, and their various sub-categories and stellations, if you wish :)

med_cat: (SH education never ends)
[personal profile] med_cat
Lemniscate, n.

: a figure-eight shaped curve whose equation in polar coordinates is ρ2=a2 cos 2θ or ρ2=a2 sin 2θ

First Known Use: circa 1781

Etymology:

New Latin lemniscata, from feminine of Latin lemniscatus with hanging ribbons, from lemniscus

In short, it's the infinity sign:



(today's word has been brought to you by my mom, who, as you might've guessed, is indeed a math teacher ;))

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[personal profile] med_cat
Icosidodecahedron is the compound of an icosahedron (an 11-sided polyhedron) and dodecahedron (a 12-sided polyhedron)



More info and illustrations can be found at Wikipedia
[identity profile] theidolhands.livejournal.com
sto·chas·tic [stoʊˈkæstɪk]:
origin: [1660] Greek; stokhos= aim, stokhastikos= able to guess; conjecturing. [1917] German; stochastik= randomly determined.



adjective (adverb: stochastically)
1. A choice made using a random variable, such as a program selecting one comment as a winner from a selection of thousands.

2. Any situation involving chance; statistics.

---

A "stochastic process" refers to an evolving (or changing) statistic based on a random variable that also is randomly selected; therefore time becomes the key factor in this process and how the results alter over a period of time. Example: The stock market or gauging how best to manage long lines in order to serve customers.
[identity profile] prettygoodword.livejournal.com
lissajous curve (LEE-suh-zhoo or lee-suh-ZHOO) or lissajous figure - n., a plane curve traced by a point executing two perpendicular, independent harmonic motions with frequencies in a simple ratio.




Two examples, with ratios of 2:1 and 2:3. Curves in the general shape of the 2:1 curve are sometimes informally called lissajous curves (as in the usage example below), but this is not technically correct. These are most commonly seen on oscilloscopes in movies, especially if made in the mid-20th century. Also seen capitalized, as it's named after French physicist Jules Antoine Lissajous, who studied them as part of investigated sound and harmonics. More information is available at the obligatory Wikipedia article and the Math Images wiki, and if you have Java here's a widget to play with.

The spacecraft glided on a beautiful lissajous curve of an orbit around the planet and its moon.

---L.
[identity profile] theidolhands.livejournal.com
ax·i·om·at·ic [ˌak-sē-ə-ˈma-tik]:
origin: [1797] Greek; axiōmatikos= honorable

adjective

1. A fact that is self-evident (prima facie); unquestionably true; universally accepted point of reason without need of evidence or additional research.

2. A mathematic principle from whence theorems are derived based on a single or series of axioms (postulates) described as formulas, such as in ancient Greek geometry, the most famous of which is Euclidean.

“It is axiomatic that one death is a tragedy, a thousand is a statistic. So it was for Mi-ran. What she didn't realize is that her indifference was an acquired survival skill. In order to get through the 1990s alive, one had to suppress any impulse to share food. To avoid going insane, one had to learn to stop caring.” ― Barbara Demick, Nothing to Envy: Ordinary Lives in North Korea



[identity profile] ellesieg.livejournal.com
v = xy

A vampire number is a number with an even number of digits that, when split into a pair of numbers with an equal number of digits (x and y) and multiplied, results in the original number (v). In the above expression, x and y are the fangs. A single vampire number may have more than one pair of fangs, as you can put its digits in any order you like.

1260 has only one pair: 21 x 60

125,460 has two pairs: 204 x 615 and 246 x 510.

24,959,017,348,650 has five pairs of fangs and likes to spend its weekends lurking in dark alleys and the woods bordering lonely rest areas: 2947050 x 8469153, 2949705 x 8461530, 4125870 x 6049395, 4129587 x 6043950 and 4230765 x 5899410.

A true vampire number has only two fangs, neither of which end in zero. Variants include vampire numbers with more than two fangs, and pseudovampire numbers, which have fangs comprised of numbers with an odd number of digits.
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[personal profile] med_cat
min·u·end noun \ˈmin-yə-ˌwend\ : a number from which the subtrahend is to be subtracted

Example:

35-5=30

35 is the minuend, 5 is the subtrahend, or:

minuend-subtrahend=difference

Etymology:

Latin minuendum, neuter of minuendus, gerundive of minuere to lessen

First Known Use: 1706

Tesseract

Jun. 3rd, 2012 03:15 am
[identity profile] theidolhands.livejournal.com
Tes·ser·act (ˈte-sə-ˌrakt):
origin: coined in A New Era of Thought (1888) by C.H. Hinton, from the Greek [τέσσερεις ακτίνες] "four rays"

noun
a.k.a. "hypercube", "tetracube", "polytope"; a hexahedron with six equal squares as faces (or a four-dimensional analog of the cube). In a real tesseract, which cannot exist in our three-dimensional space, each edge would be the same length.

➝ examples of:
➀ Variating in shape, a version of the cube is found in Salvador Dalí's Crucifixion (Corpus Hypercubus) (1953).
➁ A wrinkling of time allowing two points to be connected through a 5th dimension thus permitting time travel, used in the science-fiction novel A Wrinkle in Time (1973).
➂ Ancient Asgardian artifact of unimaginable power kept in Odin's chamber, referred to as "The Cosmic Cube" and featured in Marvel Comic's latest series of films -- culminating in The Avengers (2012).


3D image - WARNING: mesmerizing )

*request: Could we clean out the misspelled tags, please? I volunteer, if needed.


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Tessellate

May. 7th, 2010 09:37 pm
[identity profile] sakai-yukari.livejournal.com
Tessellate [tes-uh-leyt]
verb

Definition
To form a pattern using plane figures or polygons so that there are no gaps or overlaps, such as in a mosaic.

Etymology
From Latin tessellatus, 'mosaic', which comes from tessella, 'small cube', a dimunitive form of tessera, 'square'.

Usage
I'm trying to figure out how to tessellate these tiles into an appealing design for my bathroom floor.

Further Exploration
http://en.wikipedia.org/wiki/Tessellation Explains more of the mathematics behind tessellating.
http://www.shodor.org/interactivate/activities/Tessellate/# Go! Have fun using this java script application to tessellate to your heart's content!


This is my first post, so please let me know anything I can do to make this post better! Thanks!
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