474 reputation
38
bio website dfan.org/blog
location Boston, MA
age
visits member for 3 years, 3 months
seen 13 hours ago

Game programmer and designer (PC and consoles) since 1991, in C at first and then C++. I also use Python seriously and other languages semi-seriously (currently doing some hobby stuff in Clojure). Emacs zealot.

Games include Ultima Underworld, System Shock, Terra Nova: Strike Force Centauri, Frequency, Amplitude, Eyetoy: Antigrav, Guitar Hero (plus 2), Rock Band (plus 2, Beatles, 3).


Jun
4
comment 'Obvious' theorems that are actually false
You order the rationals $q_1, q_2, \ldots, q_n, \ldots$ and place an interval of $(\frac \epsilon 2)^n$ around each one, choosing $\epsilon$ to be less than $1$.
May
23
comment Are mathematical articles on Wikipedia reliable?
I was curious whether Nature had a response to the response, and they did, here and here. (I have no contribution to make regarding which side is in the right; I'm just presenting the documents for others who are curious).
May
1
comment Examples of mathematical results discovered “late”
It took a surprisingly long time (17th century) for even very basic concepts of probability theory to be developed, considering that those concepts would have been immensely valuable in real life, given that gambling has been popular forever.
Apr
17
comment Is there any shorthand notation for linear interpolation?
pic also accepts a of the way between p and q, which I suppose demonstrates the lack of a common notation.
Apr
17
comment Is there any shorthand notation for linear interpolation?
@MJD Thanks. After a little searching, it looks like the pic notation is a<p,q> and metafont's is a[p,q], so they do have the same general form.
Apr
17
awarded  Student
Apr
17
awarded  Tumbleweed
Apr
15
answered How can I learn Real Analysis in 10 days?
Apr
10
asked Is there any shorthand notation for linear interpolation?
Apr
7
answered probability: when to multiply when to add?
Apr
6
awarded  Yearling
Apr
6
revised Use Lagrange Multipliers to find the absolute extrema
Error in explanation
Apr
6
suggested suggested edit on Use Lagrange Multipliers to find the absolute extrema
Apr
5
answered higher partial derivative
Apr
4
answered Unable to understand “something out of something”
Apr
4
comment how to calculate this convolution:
That function looks a little funny. Is it possible that $u(t) - (t-T)$ is really $u(t) - u(t-T)$ and you copied it down incorrectly? I'm also a little surprised that the problem bothers to give two names $x(t)$ and $h(t)$ to the same function.
Apr
3
comment Solving $y'-y=2\cos 5t$ using the Laplace Transform
Note by the way that you can do the partial fractions part of this problem (which is most of it!) a lot easier by using the cover-up method. The time spent learning this method will have paid for itself by the time you've done two Laplace transform problems.
Apr
3
comment Solving $y'-y=2\cos 5t$ using the Laplace Transform
You can easily check your answer for $y(t)$ by just seeing whether the original differential equation holds for it.
Apr
1
comment Confusing rational numbers
I haven't checked your intermediate math, but perhaps you are expected to rationalize the denominator in your final answer?
Mar
30
comment Strategies for developing explicit formulas for nth term given recurrence relation?
The closest thing to a general method for solving recurrences is the use of generating functions, which will definitely work in this case. Searching for "generating functions recurrence" will turn up some material. If you want a textbook reference, try Concrete Mathematics by Graham, Knuth, and Patashnik, or An Introduction to the Analysis of Algorithms by Sedgewick and Flajolet.