X

# Posts

### November 24, 2014

+
We finally made it to Thanksgiving Break. This year we get a whole week!It's amazing. It's our first day off since Labor Day ... and it feels good!Big events this week ...Started decorating for Christmas yesterday ... put up the tree,Shopped for stocking stuffers yesterday at Target.Relaxed today at the movies ... Whiplash ... it was excellent.Get to catch up on laundry tomorrow AND reading!Twitter Chats ... #Alg2Chat on Monday & #Eduread on WednesdayFlying to Tennessee to see family this […]
+
This week’s puzzle comes from the 1991 film Little Man Tate. Here is how the film presents the problem. How about giving me a number that when divided by the product of its digits the quotient is 3. And if you were to add 18 to this number the digits would be inverted. In the […]
+
- If you teach slope and are looking for a fun activity to help in the days leading up to Thanksgiving, I’d love for you to try my new slope puzzle. You can find it in the “Today’s Flash Freebie!” box over there on the sidebar of my blog or the Freebies! tab on my […]
+
No, not 120 miles north, but several thousand miles west to Banff, Canada, home of the Banff International Research Station for Mathematical Innovation and Discovery. I travelled south from St Andrews to London yesterday. We went first class; the cost … Continue reading →
+
Mathematics is all about patterns. Some describe mathematics as the science of patterns, and the ability to understand patterns is described as a key concept in NCTM's algebra standard. I didn't like math growing up.  Now, it fascinates me almost to the point of obsession, and I attribute that to two things: (1) I now understand the math behind the procedures I was taught, and (2) I see the patterns that were never pointed out to me before.Since I love patterns, it should be no surprise […]
+
In analytic number theory, an arithmetic function is simply a function from the natural numbers to the real or complex numbers. (One occasionally also considers arithmetic functions taking values in more general rings than or , as in this previous blog post, but we will restrict attention here to the classical situation of real or […]
+
*************************************************************************** We apologize for multiples copies. Please circulate this CFP among your colleagues and students. *************************************************************************** [ICCTIM2015] The Second International Conference on Computing Technology and Information Management All registered papers will be submitted to IEEE for potential inclusion to IEEE Xplore Important Dates Paper due: Open from now until March […]
+
Albertus MagnusTo call in the statistician after the experiment is done may be no more than asking hm to perform a postmortem examination: he may be able to say what the experiment died of.~Fisher, Ronald AylmerThe 328th day of the year; 328 is the sum of the first fifteen primes, and is a tau-number since it is divisible by the number of divisors it has. EVENTS1639 British astronomers Jeremiah Horrocks and William Crabtree became the first observers to record a transit of Venus. Horrocks was […]

### November 23, 2014

+
Recently, longtime friend-of-the-blog Greg Kuperberg wrote a Facebook post that, with Greg’s kind permission, I’m sharing here. A parable about pseudo-skepticism in response to climate science, and science in general. Doctor: You ought to stop smoking, among other reasons because smoking causes lung cancer. Patient: Are you sure? I like to smoke. It also creates jobs. […]
+
In a cross-validated forum exchange, I used the code below to illustrate the working of an ABC algorithm: Hence I used the median and the mad as my summary statistics. And the outcome is rather surprising, for two reasons: the first one is that the posterior on the mean μ is much wider than […]
+
Stop Hating Common Core Math | SkeptoidTags: no_tagDigital Literacy Dover: To Code or not to Code?Tags: no_tagThe Magic Roundabout: why anxiety shouldn’t stop us learning | Othmar's TromboneTags: no_tagPosted from Diigo. The rest of Read on the Web -- Repository group favorite links are here.
+
Suppose we have a $2\times 2$ matrix $$M = \begin{pmatrix} x_{11} & x_{12}\\ x_{21} & x_{22} \end{pmatrix}$$ with entries in a field $F$. The characteristic polynomial of this matrix is $p(t) := {\rm det}(tI_2 – M) = t^2 – (x_{11} + x_{22})t + x_{11}x_{22} – x_{21}x_{12}$. One might ask: how can we produce […]
+
Mona Chalabi and Andrew Flowers figure out the most common name in America, using some data by Lee Hartman to correct for the fact that first name and last name are not independent, but tend to cluster based on ethnicity. … Continue reading →
+
Part 1: Pixel PioneersPart 2: Sprite SupremePart 3: Polygon RealmPart 4: Voodoo BloomPart 5: Future Crisis
+
Recently I wrote that my blog is under attack by spam comments. Most of the comments were caught by my spam-filter Akismet, the best-known filter for WordPress. I was receiving about 50,000 comments a day and 200 of them were sneaking through this filter. I had to moderate those and delete them. This was an […]
+
This is a jubilee year.* In November 1964, John Bell submitted a paper to the obscure (and now defunct) journal Physics. That paper, entitled “On the Einstein Podolsky Rosen Paradox,” changed how we think about quantum physics. The paper was … Continue reading →
+
It is one of the rules of my system of general harmony, that the present is big with the future, and that he who sees all sees in that which is that which shall be. Leibniz • Theodicy Re: Dick … Continue reading →
+
حل متراجحة جذرية تمرين محلول في ما يلي شرح لطريقة حل متراجحة تحتوي على تعبير جذري وذلك بوضع جدول اشارات دالة جذرية. الحالات التي تمت دراستها في الفيديو : <!-- mathsways336-280 --> (adsbygoogle = window.adsbygoogle || []).push({}); شاهد ايضا : المعادلات من الدرجة الثانية بمجهول واحد مع التعميل […]
+
References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Problems 10.12. Using the retarded potentials, we can find a time-dependent expression for the magnetic field to complement the equation we got earlier for the electric field. The potentials are where and The magnetic field is where we’ve used the identity We […]
+
كيف تحدد معادلة مستقيم انطلاقا من تمثيله المبياني في ما يلي شرح لطريقة تحديد معادلة مستقيم انطلاقا من تمثيله المبياني مع ثلاثة امثلة تطبيقية. <!-- mathsways336-280 --> (adsbygoogle = window.adsbygoogle || []).push({}); شاهد ايضا الدالة التآلفية والدالة الخطية، ملخص الدرس وتطبيقات ثالثة […]
+
This week I visited Washington University in St. Louis to give a colloquium, and caught up with a couple of my old foliations friends, namely Rachel Roberts and Larry Conlon. Actually, I had caught up with Rachel (to some extent) … Continue reading →
+
How would you create a table of trig functions without calculators or calculus? It’s not too hard to create a table of sines at multiples of 3°. You can use the sum-angle formula for sines sin(α+β) = sin α cos β + sin β cos α. to bootstrap your way from known values to other […]
+
Journey of Imagination   by Roovodi   http://im-possible.info/english/art/computer/roovodi.html   Author - http://roovodi.deviantart.com/
+
References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Problem 10.11. Using the retarded potentials, we can find a time-dependent expression for the electric field . The potentials are where and The expression for is given by The derivatives are complicated by the fact that the integrands in 1 and 2 […]
+
Happy Fibonacci Day (11/23)!
+
I was interested in working through a textbook on statistical mechanics, but as I’m no longer active in a physics department at a university, I was wondering what textbooks are commonly used these days. I have the book Fundamentals of Statistical and Thermal Physics by F. Reif, but this was published in 1965 and doesn’t seem […]
+
Habe ich das neulich richtig gelesen? Jan schrieb ungefähr: “Elternsprechtage sind ja immer ganz nett.” Nein, sind sie nicht. Das heißt jetzt nicht, dass ich sie schlecht finde, denn gut sind sie eigentlich schon, aber nett? Bei uns läuft vormittags Unterricht bis 13.10 Uhr und dann Elternsprechtag von 14 bis … Continue reading →
+
At the undergraduate level, sometimes functions are of two variables (x,y). How do we find the maximum or minimum points of such a function? Read the following PDF to find out! Recommended Book: Multivariable Calculus, 7th Edition This is a … Continue reading →
+
Next week I’ll be giving a lecture on spectral sequences in algebraic geometry, and in the notes I’m preparing I wanted to put the spectral sequence below the title of the corresponding section in the table of contents. The \addcontentsline command was known to me, but \addtocontents wasn’t, and there is one caveat in using […]
+
There are few things that bruise your professional ego more than no one showing up to an event you painstakingly and excitedly planned. In my case, it all came crashing down in early October. I had been planning to start … Continue reading →