2,779 reputation
2824
bio website arcsecond.wordpress.com
location Baltimore, MD
age 29
visits member for 3 years, 8 months
seen Apr 7 at 3:13

I'm a physics graduate student.


Feb
22
awarded  Nice Question
Feb
21
comment Why is Euclidean geometry scale-invariant?
Interesting point. Then all I need to do is understand how why the Pythagorean theorem is special to Euclidean geometry. The most famous proofs that pop to mind for me involve things like similar triangles, though, and so using them would be circular reasoning.
Feb
21
comment Why is Euclidean geometry scale-invariant?
@Qiaochu I know some linear algebra and a little abstract algebra from studying physics, so yes a more modern treatment would be interesting, but depending on what tools it uses I might need a reference to understand the background.
Feb
21
asked Why is Euclidean geometry scale-invariant?
Feb
21
awarded  Editor
Feb
21
revised How to find the distance between a point and line joining two points on a sphere?
changed "C" to "X" to fit with picture
Feb
21
suggested suggested edit on How to find the distance between a point and line joining two points on a sphere?
Feb
17
comment Derivation of Fourier Series?
This isn't really a physics question. I'll flag for the mods to migrate it to math.stackexchange.
Feb
3
accepted How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
Feb
3
comment How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
@wok, @Moron Thank you for the links. I saw that post before asking the question, but once I realized it was answering a slightly different question, I didn't read it in detail. I guess I should have.
Feb
3
comment How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
Yes, I get in now. The answer is just ${}_{n-r+1}C_r$. Thank you encouraging me rather than giving it away.
Feb
2
comment How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
Nice and simple. Thank you.
Feb
2
comment How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
@Moron Yes, I did search this site. I found someone talking about non-consecutive birthdays, but that's sampling with replacement, and this is without replacement. Did I miss something?
Feb
2
asked How many ways can $r$ nonconsecutive integers be chosen from the first $n$ integers?
Jan
24
accepted Why isn't the gamma function defined so that $\Gamma(n) = n! $?
Jan
20
comment Why isn't the gamma function defined so that $\Gamma(n) = n! $?
@Nate Thanks for the link. I checked Wikipedia and the archives on this site, but didn't look at MathOverflow.
Jan
20
asked Why isn't the gamma function defined so that $\Gamma(n) = n! $?
Nov
9
awarded  Supporter
Nov
9
comment How can I write the Axiom of Specification as a sentence?
Thank you, Carl. That and your comments below clear things up to the point where I realize it would take a lot of work learning axiomatic set theory to make things totally clear! I think I have the basic idea, though.
Nov
9
accepted How can I write the Axiom of Specification as a sentence?