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visits member for 2 years, 1 month
seen May 20 at 22:35

Nov
26
comment Is the number 100k+11 ever a square?
Correction -- " ... and 89 are squares" should read " ... and 89 can be squares".
Oct
30
comment How can I express the sum of $\sin a+\sin2a+\sin3a+\cdots+\sin(n-1)a$?
@Alex -- The answer posted here is very similar to what Boris Novikov has posted. Look up Telescopic sum
Oct
19
comment Calculate $\sum\limits_{n=1}^\infty (n-1)/10^n$ using pen and paper
You have an Arithmetico Geometric Series.
Oct
19
awarded  Commentator
Oct
19
comment In high school statistics, why does it seem like equations come out of the sky
" They will slaughter us in a nuclear war next week if we don't make our students [memorize a formula] " -- Awesome! :)
Oct
10
comment Solve $4^{9x-4} = 3^{9x-4}$
Try this: Solve for $x$ and $y$ when $p ^ {2x + y} = q ^ {x + y + 1}$ where $p$ and $q$ are two integers that are relatively prime to each other.
Oct
8
comment Fastest way to check if $x^y > y^x$?
Which means one has more permutations to test (I agree that it would still be far more efficient than calculating $x ^ y$ or $y ^ x$.
Oct
8
comment Fastest way to check if $x^y > y^x$?
@Henry -- Did you mean "... 1 and $e$"? When $log$'s operand is less than one, it becomes negative and one has to be careful with inequalities with one side being negative and other being positive.
Oct
5
comment Why does my calculator show $2^{-329} = 0?$
Michael Hardy -- My +1 goes to @AlvinWong whose comment explains why the typical calculator shows zero.
Jul
30
answered What is the meaning of infinitesimal?
Jun
7
comment Solving the equation $11x^2-6000x-27500 =0$, preferably without the quadratic formula
The last line should read $(y - 3000)^2 = 3050^2$
May
26
comment How do you respond to “I was always bad at math”?
@AsafKaragila -- I do not see my response for "You are getting a PhD in math?" in the pie chart -- which would be "I am so sorry!" (with a cheeky grin)
Apr
11
comment How can I prove that $xy\leq x^2+y^2$?
If $xy < 0$ then $2xy < xy$
Jun
7
awarded  Scholar
Jun
7
accepted Teaching permutations, How to?
Jun
6
comment Teaching permutations, How to?
Sincere thanks for the illustrated answer.
Jun
6
comment Teaching permutations, How to?
@AndréNicolas -- While my niece would be mighty thrilled with your response as well as explains my difficulty in explaining this to her, methinks trying to make a distinction between how many ways can you arrange and how many arrangements can be made is splitting hairs in linguistic minutiae.
Jun
5
awarded  Supporter
Jun
5
awarded  Student
Jun
5
asked Teaching permutations, How to?