1,954 reputation
1128
bio website benalpert.com
location Mountain View, CA
age
visits member for 3 years, 9 months
seen Apr 7 at 4:46

I'm a software developer originally from Boulder, CO, currently working at Khan Academy in Mountain View, CA. In my spare time, I contribute to React, make music, and cook.


Jul
24
comment How many knight's tours are there?
Tomer Vromen: I'd repost that as an answer.
Jul
24
comment Why is the derivative of a circle's area its perimeter (and similarly for spheres)?
This doesn't explain why the coefficients match up.
Jul
24
answered Balance chemical equations without trial and error?
Jul
23
asked Counting how many hands of cards use all four suits
Jul
23
comment Your favourite maths puzzles
If the size is fixed, it's easy to create a tiling that prevents finding a monochromatic triangle, but if I remember correctly, the answer is unknown in the general case.
Jul
23
comment Your favourite maths puzzles
One answer (from Proof Without Words book): gurmeetsingh.files.wordpress.com/2008/10/calissons.png
Jul
22
awarded  Critic
Jul
22
comment Can there be two distinct, continuous functions that are equal at all rationals?
Indeed I did. Thanks for catching that!
Jul
22
revised Can there be two distinct, continuous functions that are equal at all rationals?
added 11 characters in body
Jul
22
answered Can there be two distinct, continuous functions that are equal at all rationals?
Jul
22
answered Looking for a book similar to “Think of a Number”
Jul
22
answered What can we conclude from correlation?
Jul
22
comment Intuitive understanding of the derivatives of $\sin x$ and $\cos x$
@Justin L.: Whoops, I definitely misread your question and thought that it was answering itself somehow. Sorry!
Jul
22
comment What property of certain regular polygons allows them to be faces of the Platonic Solids?
The definition of "Platonic solid" requires that the faces are identical regular polygons, but apparently you're looking for some other more general definition that allows irregular polygonal faces. Why is it that you're not counting the triangular bipyramid which doesn't have regular faces? Here's a picture: upload.wikimedia.org/wikipedia/en/thumb/f/f7/…
Jul
21
comment Intuitive understanding of the derivatives of $\sin x$ and $\cos x$
I feel like maybe this should be a question asking if anyone knows of an intuitive explanation and you should write the second part of your answer as an answer. (See meta.stackoverflow.com/questions/17463).
Jul
21
awarded  Student
Jul
21
awarded  Editor
Jul
21
revised Tiling a 3 by 2n rectangle with dominoes
added 1 characters in body
Jul
21
asked Tiling a 3 by 2n rectangle with dominoes
Jul
21
comment Best Intermediate/Advanced Computer Science book
I think this would be more appropriate at Stack Overflow, no?