# robjohn

West Hills, CA

none

Age: 56

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

aka Rob Johnson

$\LaTeX$ support for Chat

 3h revised Series about Euler-Maclaurin formulaadd absolute values 20h awarded Enlightened 20h awarded Nice Answer 1d revised Show $\int_0^1 \frac{\log(1-x)}{x}dx=-\frac{\pi^2}{6}$extend the result 2d answered Show $\int_0^1 \frac{\log(1-x)}{x}dx=-\frac{\pi^2}{6}$ 2d comment 2nd degree differential equationTo get more upvotes, consider this post. 2d comment 2nd degree differential equationThe method to look up would be Integrating Factors. Apr 29 answered 2nd degree differential equation Apr 28 answered Calculate point coordinates from other points Apr 27 answered arithmetic mean of smallest numbers of all subsets of r elements formed out of (1,2,..n) Apr 26 revised Poisson distribution- mosquitos questionfix typo Apr 26 answered Poisson distribution- mosquitos question Apr 26 comment Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$Doh! Sorry about that. Apr 26 revised Contour Integral of $\int\limits_0^{2\pi}\frac{d\theta}{1+a\cos\theta}$ for $a^2<1$ (textbook wrong?)add a real method verification Apr 26 comment Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$ Apr 26 revised Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$fix typo Apr 26 answered Is there an inequality for $\sinh(x)$ which is similar to this inequality $\cosh(x)\leq e^{x^2/2}$ Apr 26 answered Contour Integral of $\int\limits_0^{2\pi}\frac{d\theta}{1+a\cos\theta}$ for $a^2<1$ (textbook wrong?) Apr 25 comment Normal system of the least square methodI thought you were wondering why the factor of $2$ was not in the derivative of $\|Pa-y\|$. I didn't think you were concerned about the factor of $2$ in $2P^T(Pa-y)=0$ since $2x=0\iff x=0$. What is it that is bothering you about the factor of $2$? Apr 25 comment Normal system of the least square method@MarcZ: If the addendum does not answer your question, let me know.