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the mean square The Mean Square
(with one standard deviation and several unusual ones)

aka Rob Johnson

$\LaTeX$ support for Chat


Nov
29
awarded  fourier-series
Nov
28
awarded  Necromancer
Nov
28
revised $\sum_{n=1}^\infty(n\ \text{arccot}\ n-1)$
Simplify a bit
Nov
28
answered $\sum_{n=1}^\infty(n\ \text{arccot}\ n-1)$
Nov
28
comment $\sum_{n=1}^\infty(n\ \text{arccot}\ n-1)$
@VladimirReshetnikov: has it been a bit, yet?
Nov
28
comment Commutation of exponentials of matrices
@DanielFischer: why not make this an answer?
Nov
28
comment Trigonometry triangles
@user110892: $(150+F\cos(50))^2=150^2+\color{#C00000}{2\cdot150}F\cos(50)+F^2\cos^2(50)$
Nov
28
revised How many integers from $1$ through $999,999$ contains digit $1$?
added 5 characters in body
Nov
28
comment How many integers from $1$ through $999,999$ contains digit $1$?
$10^6\times\left(\frac9{10}\right)^6=9^6$ which is exactly what Asaf's hint gives.
Nov
28
answered How many integers from $1$ through $999,999$ contains digit $1$?
Nov
28
answered Show that $(x_n)$ is decreasing and find its limit.
Nov
28
awarded  Nice Answer
Nov
28
revised Show that $ \sum_{n=2}^m {\vphantom{+1}n \choose 2} = {m+1 \choose 3}$
improved sizing of title
Nov
28
revised Evaluating $\int_{x=0}^{x=\sqrt6}\int_{y=-x}^{y=x}\mathrm{d}y\,\mathrm{d}x$
LaTeXified
Nov
27
answered Math induction sum of even numbers
Nov
27
comment Find $x$ and $y$ in $2^{x-y} + 1 = 2^x,$ where $x,y$ are integers
Nice complete argument +1
Nov
27
answered Find $x$ and $y$ in $2^{x-y} + 1 = 2^x,$ where $x,y$ are integers
Nov
27
comment Pigeonhole Principle Homework Problem
Your answer is more pigeon-holy.
Nov
27
comment Pigeonhole Principle Homework Problem
I hope my answer is not too close. I tried to make it different, but there are not too many ways :-)
Nov
27
answered Pigeonhole Principle Homework Problem