2,114 reputation
1230
bio website benalpert.com
location Mountain View, CA
age
visits member for 4 years, 5 months
seen Dec 8 at 22:29

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.


Jun
21
comment Proving Stewart's theorem without trig
Thanks, your answer is definitely good enough for my purposes. Good night!
Jun
21
comment Proving Stewart's theorem without trig
Very nice, thanks!
Jun
21
accepted Proving Stewart's theorem without trig
Jun
21
asked Proving Stewart's theorem without trig
May
26
awarded  Nice Answer
May
15
comment Function $F$ that $F(x)+F(-x)=\lim_{y\rightarrow\infty}F(y), \forall x \in \mathbb{R}$
@Tim: Might want to change the title too.
May
10
comment Calculate intersection of 2 points
@J.M. I'm pretty sure Ross Millikan interpreted it right. You have two points and two slopes given as angles from the vertical ($\pi/2$) and want the intersection between the two lines thus determined.
May
4
revised How to accurately calculate the error function erf(x) with a computer?
fix broken link!
May
4
suggested approved edit on How to accurately calculate the error function erf(x) with a computer?
Apr
28
comment Why the name 'FACTORIAL'?
But that's true of other numbers (both smaller and larger) that aren't the factorial.
Apr
27
revised How to solve this recurrence relation? (convolution integral)
edited tags
Apr
27
revised When is a recurrence relation linear
edited tags
Apr
27
revised There is a table of the complexity of recursive algoritms?
edited tags
Apr
26
comment Calculating the highest possible damage achievable using 6 items from a pool of ~25
Probably belongs on SO.
Apr
25
comment Inclusion-exclusion principle: Number of integer solutions to equations
@DAK: Reread Gerry's last paragraph. For the intersection of $A_1$ and $A_2$, it's equivalent to solving $v_1+v_2+y_3+y_4=5$ with $v_1, v_2, y_3, y_4 \ge 0$. Just like the number of solutions to solve $y_1+y_2+y_3+y_4 = 12$ is $C(15,3)$, the number of solutions to that equation (and the size of the $\lvert A_1 \cap A_2 \rvert$ set) is $C(8,3)$.
Apr
25
comment Inclusion-exclusion principle: Number of integer solutions to equations
I agree, I think it's $C(12 + 4 - 1, 3) = C(15,3)$.
Apr
16
awarded  Nice Question
Apr
13
comment Can (x'y' + xy) be simplified?
@Brandon: You should probably write that as an answer.
Apr
13
comment Draw customized (calculus) graphs like these?
Not sure whether to flag it, but I have enough rep to retag stuff so I got rid of the graph-theory tag.
Apr
13
revised Draw customized (calculus) graphs like these?
edited tags