MATHEMATICS

Kamis, 15 Desember 2011

Stirling numbers of the first kind.

Definition. S1[n,k] (Stirling number of the first kind) is the number of permutations of length n containing k cycles, multiplied by the sign of these permutations.

Example: 
Permutation Cycles
123 (1)(2)(3)
132 (1)(23)
213 (12)(3)
231 (123)
312 (132)
321 (13)(2)
Thus:
S1[3,1]=2
S1[3,2]=-3
S1[3,3]=1

Stirling Numbers of the first kind are implemented in Mathematica as StirlingS1.

December 15, 2011





MAA's 3 Books. 3 Days Sale is back for JMM 2012!


Rabu, 14 Desember 2011

Grup Matematika di Facebook

Siapa yang tak kenal dengan satu ini. Facebook (FB) adalah website jejaring sosial yang memudahkan kita saling berkomunikasi di dunia maya. Dari segi itulah akhirnya muncul Grup-Grup dengan ciri khasnya masing-masing. Berikut Grup Matematika yang berhasil saya dapatkan. Jika ada informasi lain, mohon bantuannya untung sharring di sini :

December 14, 2011




MAA's 3 Books. 3 Days Sale is back for JMM 2012!

Higgs boson and the Euro

Yesterday CERN announced in a press release that 'they almost found the Higgs boson particle'. To me that sounds like a programmer telling me that his code is almost finished. 'It's 99% done'. ( The worst thing I ever heard was 'I'll finish the design when I am done coding.'. ) Anyway, they must get really nervous at CERN for budget cuts in these terrible economic times. - People at CERN rather don't communicate with common people. Unfortunately they depend upon our tax money to fund their expensive toy, the LHC. That's why they are always close to finding something, or they -think- that something exceeded the speed of light. As long as we pay their toy while everywhere else people are bleeding.

Tes Online Invir.Com

Tes Online dibawah ini ditujukan bagi siswa-siswi SD/SMP/SMA yang ingin menguji sudah sampai sejauh mana pemahaman mereka dalam menguasai materi pelajaran yang diberikan oleh bapak/ibu guru di dalam kelas selama 6 tahun (SD) / 3 tahun (SMP/SMA) belajar di sekolah.

Mudah-mudahan bermanfaat dalam persiapan menghadapi Ujian Nasional nanti.

Berikut ini adalah link untuk mengikuti soal ujian online. Silakan klik mata pelajaran yang dituju.

1. SMP/MTs

Untuk SMP/MTs ada 4 mata pelajaran yang dimasukkan, yaitu Matematika, IPA, Bahasa Indonesia, dan Bahasa Inggris


Tahun 2008MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2007MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2006MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2005MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2004MatematikaI P ABahasa IndonesiaBahasa Inggris

Tahun 2003MatematikaI P ABahasa IndonesiaBahasa Inggris

2. SD/MI

Untuk SD/MI ada 4 mata pelajaran yang dimasukkan, yaitu Matematika, IPA, Bahasa Indonesia, dan Bahasa Inggris.

Tahun 2008MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2007MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2006MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2005MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2004MatematikaI P ABahasa IndonesiaBahasa Inggris
Tahun 2003MatematikaI P ABahasa IndonesiaI P S

3. SMA/MA

Untuk SMA/MA ada 10 mata pelajaran yang dimasukkan, yaitu Matematika, Fisika, Kimia, Biologi, Bahasa Indonesia, Bahasa Inggris, Ekonomi, Sosiologi, PKn, dan Sejarah.

Tahun 2008 Matematika Fisika Kimia Biologi Indonesia B. Inggris Ekonomi Sosiologi P Kn Sejarah
Tahun 2007 Matematika Fisika Kimia Biologi Indonesia B. Inggris Ekonomi Sosiologi P Kn
Tahun 2006 Matematika Fisika Kimia Biologi Indonesia B. Inggris Ekonomi Sosiologi P Kn
Tahun 2005 Matematika Fisika Kimia Biologi Indonesia B. Inggris Ekonomi
P Kn
Tahun 2004 Matematika Fisika Kimia Biologi Indonesia B. Inggris Ekonomi
P Kn
Tahun 2003 Matematika Fisika Kimia Biologi B. Indonesia B. Inggris Ekonomi
P Kn

Selasa, 13 Desember 2011

December 13, 2011




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Fearless Symmetry 3/23: Permutations

I read the third chapter of Fearless Symmetry.

Part 1: Algebraic Preliminaries

Chapter 3: Permutations

In chapter 3 the concept of a permutation is explained and how they form groups.

Definition: A permutation is a one-to-one map from a set to itself.

Example 1:
Given the set {1,2} the possible one-to-one maps ( permutations ) are:
1->1, 2->2 and
1->2, 2->1.

Example 2:
For sets of three elements there are 6 = 3! possible permutations.

If we put all the permutations of a set in a set by itself and add the composition of permutations as the operation then this set becomes a group. Permutation groups are among the most important objects in group theory because every finite group is a subgroup of some permutation group.

There are two possible ways of notation when it comes to permutations. Let's consider the set {1,2,3,4} which has 24 possible permutations.

The permutation 1->1, 2->2, 3->4 and 4->3 can be written as [1 2 4 3] and also as (1)(2)(3 4) or short (3 4) this is the so called cycle notation. Thus (1 2 3) and [2 3 1] represent the same permutation. Clearly the cycle notation is more efficient, especially when considering permutations of large sets.

The composition of permutations means permuting one after the other. Unfortunately in some books it is done from left to right, in others from right to left.

Exercise 1:
Show that (ab)(cde)*(ae)(bc)(d)=(ac)(bde).

( I would solve it as follows: )
Right hand side:
A B C D E
_ D _ E B Apply (bde)
C D A E B Apply (ac)

Left hand side:
A B C D E
_ _ _ D _ Apply (d)
_ C B D _ Apply (bc)
E C B D A Apply (ae)

E C B D A
C D _ E _ Apply (cde)
C D A E B Apply (ab)

And it shows that LHS = RHS


Sets of permution form a group under composition because:
- composition leads to a new permutation ( closure )
- the neutral element is the do-nothing permutation, i.e. (1)(2)(3).
- every permutation has an inverse because it can be permuted back to the original positions.
- composition of permutations is associative.

Note that the composition of permutations is NOT ( always ) commutative.

To be continued with 4. Modular Arithmetic

M381 'Challenge Exercise' - Revisited

Sorry, Paddy and Jobidaker for the late reply. ( Auto-accepting comments has its drawbacks too. )

My solution for the 1/2, 1/3, 1/5 and 1/7 case is the following. Follow the pattern for the solution to the general case. Click to enlarge pic.


Please let me know if you think a smaller number qualifies.

Kuis Persamaan Garis Lurus

Senin, 12 Desember 2011

Kisi-kisi UN 2012 Diberikan Akhir Tahun Ini

JAKARTA, KOMPAS.com - Kementerian Pendidikan dan Kebudayaan akan mempercepat waktu pemberian kisi-kisi soal ujian nasional (UN) 2012. Kisi-kisi soal akan diberikan pada akhir tahun 2011 ini. Kepala Badan Penelitian dan Pengembangan Kemdikbud Khairil Anwar Notodiputro mengatakan, hal itu dilakukan untuk membantu sekolah dan para siswa lebih siap menghadapi UN tahun depan.

Khairil menjelaskan, rencana tersebut merupakan langkah untuk meningkatkan akseptabilitas, dan juga merupakan jawaban atas banyaknya masukan terkait penyelenggaraan UN. Dari sekian banyak masukan, yang kemudian dijadikan fokus oleh Balitbang Kemdikbud adalah akseptabilitas, kualitas, dan efektifitas penyelenggaraan UN.

"Dari sekian banyak rekomendasi yang disampaikan, yang paling banyak dipersoalkan adalah akseptabilitasnya," kata Khairil, kepada Kompas.com, Senin (7/11/2011), di Kemdikbud Jakarta.

Peningkatan akseptabilitas UN dinilai akan meminimalisir "ketakutan" para siswa dan guru saat akan menghadapi UN. Cara yang ditempuh adalah dengan melakukan dialog secara lebih intensif, dan memberikan kisi-kisi UN secepatnya.

Pemberian kisi-kisi UN juga bertujuan agar memudahkan pusat memberikan arahan kepada dinas pendidikan daerah dan guru-guru di sekolah agar pembuatan soal-soal ujian di sekolah merujuk dan disesuaikan dengan kisi-kisi UN yang diberikan.

"Ketakutan itu akan memicu penolakan. Untuk menekan itu, kita berencana menyampaikan kisi-kisi secepatnya. Jika dulu berbarengan, maka sekarang kisi-kisi UN 2012 akan kita berikan di tahun 2011, ini agar tercipta keselarasan soal dan membuat siswa terbiasa dengan soal yang akan diberikan" jelasnya.

Selain itu, hal lain yang akan dipertegas adalah memberikan pemahaman kepada seluruh masyarakat bahwa UN bukanlah satu-satunya penentu kelulusan. Meski proporsi penilaiannya membuat nilai UN mendominasi kelulusan, yaitu 60 persen nilai UN dan 40 persen nilai sekolah.

"Saya harap UN 2012 bisa lebih santai dan diterima. Secara politik, proporsi 60:40 itu sudah diterima, dan baru akan dievaluasi apakah tetap digunakan atau akan diubah setelah dua tahun digunakan, yaitu pada 2013," tuturnya.

"Nilai-nilai UN yang rendah juga dalam proses pengkajian. Ujungnya kita berharap ada kebijakan berdasarkan pengkajian mengapa nilainya menjadi rendah, apakah soal yang terlalu susah atau ada penyebab lain," tambah Khairil.

Sumber : KOMPAS.com

December 12, 2011





MAA's 3 Books. 3 Days Sale is back for JMM 2012!


Minggu, 11 Desember 2011

ബഹുപദങ്ങളില്‍ നിന്നും പരിശീലന ചോദ്യങ്ങള്‍


പത്താംക്ലാസിലെ ബഹുപദങ്ങളില്‍ നിന്നുള്ള പരിശീലന ചോദ്യങ്ങളാണ് ഇന്നത്തെ പോസ്റ്റ് . ബഹുപദത്തെ ദ്വിപദം കൊണ്ടുള്ള ഹരണക്രിയയിലൂടെ ശിഷ്ടം കാണുന്നത്, ഗുണോത്തരങ്ങള്‍ തുലനം ചെയ്തുകൊണ്ട് ശിഷ്ടം കാണുന്നത്, ശിഷ്ടസിദ്ധാന്തവും പ്രയോഗവും , ഘടകസിദ്ധാന്തം , അതിന്റെ വിവിധ സാഹചര്യങ്ങളിലുള്ള പ്രയോഗം , ഘടകമാണോ എന്ന പരിശോധന, ഘടകമാണെന്ന് തന്നിരുന്നാല്‍ ചില ഗുണോത്തരങ്ങള്‍ കണ്ടെത്തല്‍ എന്നിങ്ങനെ പരമാവധി മേഖലകളില്‍ നിന്നും ചോദ്യങ്ങള്‍ ചേര്‍ത്തിട്ടുണ്ട്. ചുവടെയുള്ള ലിങ്കില്‍ നിന്നും അവ ഡൗണ്‍ലോഡ് ചെയ്തെടുക്കാം.

പരിക്ഷ കഴിയുന്ന മുറയ്ക്ക് SCERT പ്രസിദ്ധീകരിച്ച ചോദ്യബാങ്ക് നമുക്ക് തുറന്നുതരുമെന്ന് പ്രതീക്ഷിക്കാം. കേരളത്തിലെ എല്ലാ ജില്ലകളിലും തയ്യാറാക്കിയ ചോദ്യപേപ്പറുകള്‍ പരീക്ഷകഴിഞ്ഞ് അയച്ചു തന്നാല്‍ ഒന്നിച്ച് പോസ്റ്റായി പ്രസിദ്ധീകരിക്കാന്‍ തയ്യാറാണ്. അനേകം അധ്യാപകര്‍ക്കും കുട്ടികള്‍ക്കും മാതാപിതാക്കള്‍ക്കും അത് ഉപകാരപ്രദമായിരിക്കും. ഏതാനും യൂണിറ്റുകളുടെ കൂടി ചോദ്യങ്ങള്‍ പ്രസിദ്ധീകരിക്കാനുണ്ട്. അതിന്റെ പണിപ്പുരയിലാണ്. ഓരോ പോസ്റ്റിനോടൊപ്പം കൃഷ്ണന്‍ സര്‍ അയച്ചു തരുന്ന പുതിയ ചോദ്യങ്ങള്‍ കൂടിയാകുമ്പോള്‍ അതൊരു മുതല്‍ക്കൂട്ടാകും. പിന്നെ നമ്മുടെ ഹിത ചോദ്യങ്ങള്‍ അയച്ചുതരും .

പരീക്ഷകഴിഞ്ഞ് പ്രത്യേക റിവിഷന്‍ പാക്കേജ് പ്രസിദ്ധീകരിക്കാന്‍ തയ്യാറെടുക്കുകയാണ്. ഗണിതപഠനത്തില്‍ പിന്നോക്കം നില്‍ക്കുന്ന കുട്ടികള്‍ക്കായി പ്രത്യേക വിഭവങ്ങള്‍ വേണമെന്ന് ആവശ്യപ്പെട്ട് ധാരാളം മെയിലുകള്‍ വരുന്നുണ്ട് . അതിനേക്കുറിച്ചും ഗൗരവത്തോടെ തന്നെ ആലോചിക്കുന്നുണ്ട് . ഓരോ കരിക്കുലാര്‍ ഒബ്‌ജറ്റീവിനെയും അടിസ്ഥാനമാക്കി അടിസ്ഥാനചോദ്യങ്ങള്‍ അത്തരം പാക്കേജില്‍ ഉണ്ടാകും .ഗണിതാദ്ധ്യാപകരുടെയും കുട്ടികളുടെയും മറ്റ് അഭ്യുദയകാംക്ഷികളുടെയും സഹകരണം പ്രതീക്ഷിക്കുന്നു.

ബഹുപദങ്ങളിലെ ചോദ്യങ്ങള്‍ക്കായി ഇവിടെ ക്ലിക്ക് ചെയ്യുക

Rigor and Relevance in Parallel

(The math is at the end of this one.)

Last week I had one of those teaching collisions where it felt like every idea was dovetailing.  First some twitterer retweeted Terie Engelbrecht's post on rigor and relevance in the context of motivating students with respect not points. Her post was a riff on this International Center for Leadership in Education chart. My preservice high school teachers had asked for parallel lines, circles and proof for our geometry topic.  Elissa Miller tweeted about parallel lines in a way that also brought up relevance.

Rigor, Relevance, Relationships

Fig 1.1 from this ASCD article
Some comments from my colleague Dave Coffey connected the Relevance framework to the Levels of Transfer, a professional development framework from Joyce and Showers. Before I switched to a communication framework, I tried to grade using that framework! Very ingenuous, as most students are not at an executive level of transfer, and it is not fair as an expectation for a large quantity of work. I did like the sense of ownership that it promoted, and the encouragement for students to show that they had made the learning their own. When it came time to convert to grades, Integrated Use was an A, and Executive an A+. Is that fair?

Terie's central question was: 'So why not change the "doing the work for points" idea into a "doing the work to improve my learning?" idea?' This has been an issue all semester with this particular group of students for me. Because this is a teaching class, we've even explicitly discussed from whence comes thier lack of responsibility. (As in the Condition of Learning, Responsibility; not as in a guilt trip from your parents. I hope.)

So I brought the framework into class and asked them to classify the kind of lessons they saw in observation... 10 to 15 lessons over the course of the semester.  I was seriously surprised how well distributed the X's were on the relevance framework, but not surprised by the low range of rigor. The students discussed how the ABCD was confusing, as D was the "best." They had quite an interesting discussion about whether math should be 'real world' or not. You all know the discussion: why do they ask us (math teachers)? Do they ask their history teacher? What about learning the math for math's sake? Sometimes the applications are so artificial.  The students hate the applications so much, why make them do them?

I think, from their discussions as well as their observation journals, I would have put most of their X's in A.  The application in the rigor framework led to a lot of the marks being along that line, as we haven't studied Bloom's, nor have they in other classes.  Personally, I do wonder about what the classroom should look like in terms of this scale. I like the idea of flexible access, and I want students to transition to analysis, synthesis and evaluation. The application framework seems like you do want a diversity of those problem types. Regardless, I'm really interested in what other teachers think about the framework.

To support the students in thinking about implementing this, I brought what I had thought of after Elissa's prompt. Their task:
Our question is: how can we plan a lesson or lessons that will support our students in moving towards being able to make proofs, understanding the required angle content, and engaging them all the while?
Consider the following and please add your own:
a) a puzzle made from parallels and transversals
b) a map of city streets
c) a classic Japanese problem using these ideas
Where do these ideas fall on the rigor/relevance chart? How should we sequence them or structure class to get to our objective?
Explore the activities in your groups, or design your own, and then we’ll come back together to discuss the ideas.
The puzzle: (Actually revised a bit from their use, based on play; changes were made to make it more accessible and focus on the mathematical properties. Click on the image for full size.)

The map: (Grand Rapids)


Tasks suggested for this were identifying parallel and perpendicular lines, vertical and transversal pairs of angles, combining measurement of street intersections, make informal arguments for congruent pairs, etc.

The Japanese angle problem:
(The top angle is 50 degrees, the bottom 30 degrees.)


Find the angle x. “Please solve the problem and if you can make an explanation that is amazing.” From the TIMSS video at http://timssvideo.com/66 (Love this problem; thanks to Rebecca Walker who first found it.)

Students tried all three, and they typically wanted a combination of them in their lessons for their hypothetical students.  The discussion of rigor in these problems gave us a lot of material (by which I guess I mean gave me a lot of informal assessment data) for a discussion of answer, solution, argument, proof in a later class.

I think these problems are pretty good samples of A, B and C lessons; I confess to being a bit stumped as to what a D lesson/problem/activity might be for this topic. The nature of abstraction in mathematics will lead to a lot of good lessons proceeding from B to C. Opportunities to venture onto D might be more rare. I'm very curious to hear what other people think.

Fearless Symmetry 2/23: Groups

I read the second chapter of Fearless Symmetry.

Part 1: Algebraic Preliminaries

Chapter 2: Groups

Definition: A group G is a set with a composition defined on pairs of elements, as long as three axioms hold true:
1. For any three elements x,y,z in G: x*(y*z) = x*(y*z)
2. G contains an element e such that for all x in G: x*e = e*x = x.
3. For any element x in G, there is an element y in G such that x*y=e.

Example 1:
The group of rotations of the sphere in R3: SO(3) or the Special Orthogonal Group in 3 dimensions. -The set G is the collection of all rotational symmetries of the sphere, i.e. if we rotate the sphere by any angle, the sphere doesn't noticeably change. The group property basically means that if we rotate the sphere over any angle A, after this over an angle B, it is the same if we would have rotated it in one go, but over some different angle. Also any rotation has an inverse: rotating it over the opposite angle. This makes the rotations a group. SO(3) is in fact a Lie group because these rotations can be done arbitrary small which is not the case when considering the symmetry group of for example a cube. Lie groups capture the concept of "continuous symmetries".

For me personally, this is the time to review chapters 1,2 and 3 of Naive Lie Theory by John Stillwell, Springer 2008. There you will find that the ( 4 dimensional ) quaternions are intimately related to the group SO(3) and that the quaternions can be expressed as 'complex 2-dimensional rotations' or complex 2 by 2 matrices. - This explains why quaternions are frequently used in 3D-(game)-programming.

To be continued with 3. Permutations