Comments for Math 老师

Comment on Expected Value for Highest Roll on Two Dice by David Flint

David Flint — Wed, 24 Apr 2013 15:11:35 +0000

The form for just the expectation value of rolling 2 dice of size n and choosing the highest is:

(n+1)/n * [ (2n+1)/3 - 1/2]

Comment on Expected Value for Highest Roll on Two Dice by David Flint

David Flint — Wed, 24 Apr 2013 14:57:43 +0000

Sorry, that form is actually for the difference between the expected values of rolling one die, and and rolling two and choosing the highest.

Comment on Expected Value for Highest Roll on Two Dice by David Flint

David Flint — Wed, 24 Apr 2013 14:51:38 +0000

Having just worked this out myself, that summation can be reduced to the following form for any die with an even number of faces, n:

(n+1)/n*[(2n+1)/3 - (n+1)/2]

Comment on Blue Sky HTML Editor by Mr. Wang

Mr. Wang — Tue, 05 Feb 2013 17:56:26 +0000

User files are stored locally and Blue Sky runs entirely in the user’s own web browser so there’s no danger to either the server Blue Sky is stored on or other users’ files. The fact that you can write your own Javascript and see it run in the preview pane was an unintended perk!

Comment on Blue Sky HTML Editor by David Wees

David Wees — Tue, 05 Feb 2013 16:54:34 +0000

I’m not sure if this is a security issue or not, but I noticed that the script tag is fully allowed, which means people could in theory run arbitrary Javascript in your editor. This probably not a big deal, unless users have a way to access each other’s files.

Comment on Fibonacci and Exponential Growth by Debapriya Maji

Debapriya Maji — Sun, 30 Sep 2012 11:47:36 +0000

Hello sir ,is there any methode to prove that the ratio tends to 1.6 as n tends to unfinity

Comment on Ticket to Ride by Derek Thompson

Derek Thompson — Tue, 11 Sep 2012 20:37:11 +0000

Hi, I couldn’t find another way to contact you. I’m a board game blogger, but I’m also a mathematician finishing up my PHD. I intend to talk about using board games in classrooms for the fall meeting of the Indiana section of the Mathematics Association of America. Can I use your Ticket to Ride and Carcassonne examples of graph theory? Thanks!

Comment on Between the Folds by mark piper

mark piper — Fri, 23 Mar 2012 02:48:28 +0000

I am wanting to make one of these, but as per the method shown on Cory’s blog:
http://mathcraft.wonderhowto.com/blog/make-platonic-solids-out-playing-cards-0130512/ …. the thing is, I am wanting to make it out of 30 sheets of 1200×2400 12mm ply! I have the template from Cory’s blog: the issue is, the slots need to be cut on an angle, and I am having trouble calculating what that angle of the cut is… Any chance you can issue this as challenge to your readers (or you!). Many thanks, Mark

Comment on What’s Wrong With This Graph? by mark piper

mark piper — Thu, 22 Mar 2012 02:39:42 +0000

It’s not what is wrong with the bars, they are fine, as long as the creator of the graph puts the values on the axes… especially the horizontal one!

Comment on All the M&Ms You Want by Brendan

Brendan — Wed, 22 Feb 2012 03:48:25 +0000

This is great! What language is this programmed in?