5,925 reputation
31752
bio website ophirgame.com
location United States
age 72
visits member for 3 years, 8 months
seen Aug 24 at 22:58

(update) - I'm having a board game published! We'd appreciate your support on Facebook or on Twitter, as we prepare for a Kickstarter campaign in early 2014.


I hereby commit to contributing to this site without any rudeness, sarcasm, accusation, or any other unloving speech.


Sep
30
awarded  Explainer
Aug
2
awarded  Nice Question
Jul
29
comment Simplify $S=\sum_{i=0}^{k}a_i (2n)^{2i+1}$
What have you tried? etc.
Jul
28
comment Surjective function - proving
Surjective means that for any point b in the codomain, you can find a point a in the domain such that $$f(a) = b$$. If you can't "get to" certain (positive values), then the function is not surjective.
Jul
27
awarded  Popular Question
Jul
2
awarded  Curious
Jun
5
awarded  Revival
Apr
18
awarded  Popular Question
Apr
6
comment Proving $\sqrt 3$ is irrational.
Getting a downvote two years later - priceless!
Mar
6
awarded  Yearling
Mar
3
comment Prove that any palindrome with an even number of digits is divisible by 11.
You might be making this too difficult. Do you know the basic test for divisibility by $11$?
Feb
21
awarded  Nice Question
Jan
8
comment Probability that a chosen number will be a Fibonacci number
Natural density on wikipedia
Jan
7
comment The Curve in $R^n$
I would upvote this, but you have $8008$ rep...
Jan
6
comment “Bad” Mathematics in Movies
Related Huff post article
Dec
19
comment Derive $y=x\cos^3(5x+1)$
Sounds like you should do a web/video search of "chain rule", Dipok!
Dec
19
comment rank of a matrix series
@Shi/Sivaram/Marvis/17762/etc. - one day, your pride will destroy you. You are intelligent, and maybe more than most in these parts, but the cancerous attitude that your embrace can only end in loneliness and misery. Good luck out there.
Dec
18
comment Find both pairs of numbers that satisfy $\gcd(x,y)= \frac{1}{5}y$ and $x=y-3$
An ordered pair, in this context, is the gcd of said pair. Also, good to see some color back in these parts!
Dec
18
comment If $x^2+y^2=z^2$ has a solution then $5$ divides $xyz$
@EpicGuy: all this talk about "divides" kinda implies that we're dealing with integers only (which we are)...
Dec
18
comment In any Pythagorean triplet at least one of them is divisible by $2$, $3$ and $5$.
Square $1,2,3,4,5$. Then divide each by $2,3,5$ and consider their remainders.