X

Sidebar

Filters

+

As just posted on twitter.com/dmarain@gmail... Using only "mental math" explain why 173^4+179^4+183 is not prime. Should 5th graders be expected to understand this? VISIT ME DAILY ON TWITTER AT twitter.com/dmarain

+

Image source: http://www.reddit.com/r/gif/comments/1qm8tw/fireworks/ Image source: http://mathforum.org/mathimages/index.php/Envelope Image source: http://mathforum.org/mathimages/index.php/Envelope visualizingmath:To those who celebrate it, Happy Independence Day! Enjoy the parabolic envelopes that form while those bright, sparkling, parabolic curves are etched into the sky tonight…

+

I was planning to blog this Fourth of July something about Independent variables, given the nature of the day, but something else came up. I was reading Twitter, which I do way more often than is probably healthy, and I saw another image posted (or reposted) by Jo Morgan (@mathsjem), which was a simple puzzle with 7 circles, arranged in 2 columns of three and an extra circle in the middle, such that there were three lines of numbers. The center circle was filled in with a number and you had
[…]

+

The law \( {P_n} \) of a random vector \( {X=(X_1,\ldots,X_n)} \) on a product space \( {\mathbb{S}^n} \) is exchangeable when it is invariant by permutation of the coordinates: \[ \forall f:\mathbb{S}\rightarrow\mathbb{R},\quad \forall\sigma\in\Sigma_n,\quad \int\!f\,dP_n=\int\!f_\sigma\,P_n \] where \( {f_\sigma(x):=f(x_\sigma)} \) and \( {x_\sigma:=(x_{\sigma(1)},\ldots,x_{\sigma(n)})} \), and where \( {\Sigma_n} \) is the symmetric group formed by […]

michiexile tweeted: @michiexile

RT @slatestarcodex: Theory: July 4th is sublimated Midsummer in the same way Christmas is sublimated Yule and Easter is sublimated celebrat…

2015-07-05 08:55:14

rmathematicus tweeted: @rmathematicus

RT @ferwen: Death on the ice: the last expedition of Marc Cornelissen and Philip de Roo http://t.co/iPXPM84rUW

2015-07-05 08:42:55

rmathematicus tweeted: @rmathematicus

RT @JasminandRoses: Did Twitter save Bletchley Park? Brilliant talk @Dr_Black #CodeBreakers #Enigma #WomenWhoCode https://t.co/XVYLhj54pt h…

2015-07-05 08:33:01

rmathematicus tweeted: @rmathematicus

Newton's Principia was not published on 5 July 1687 – Published on… – https://t.co/WSru2UnzfZ <= Vaults Post

2015-07-05 08:20:45

rmathematicus tweeted: @rmathematicus

RT @David_Bressan: July 5, 1805: Birthday of Captain Robert Fitz Roy of the "Beagle", introduced C. Darwin to principles of Geology http://…

2015-07-05 08:18:27

rmathematicus tweeted: @rmathematicus

RT @hist_astro: Happy Birthday to Henrietta Swan Leavitt, born #OTD in 1868. One of Harvard College Observatory's female "computers". http:…

2015-07-05 08:18:11

rmathematicus tweeted: @rmathematicus

RT @NautilusMag: Franklin is often thought of as the ultimate Revolutionary inventor. But what of Jefferson and his cannonball clock? http:…

2015-07-05 08:15:51

rmathematicus tweeted: @rmathematicus

RT @ARWallace: Wallace Medal | The Alfred Russel Wallace Website http://t.co/lERNiMw7fo

2015-07-05 08:13:34

X