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 May 11 accepted Notation for a vector with constant equal components of arbitrary dimension May 11 comment Notation for a vector with constant equal components of arbitrary dimension Thanks. I also saw this article mathoverflow.net/questions/9898/… May 11 comment Notation for a vector with constant equal components of arbitrary dimension Is this standard? May 11 asked Notation for a vector with constant equal components of arbitrary dimension May 11 comment Notation for replacing a matrix column with a vector Thank you, that's good too. I will have a think about this with respect to my work :-) May 10 accepted Notation for replacing a matrix column with a vector May 10 comment Notation for replacing a matrix column with a vector Thank you that's great. Nice notation ! May 10 comment Notation for replacing a matrix column with a vector Thanks, I was looking for something similar to this. I was going to use $A_j[v]$ before you answered my question. May 10 asked Notation for replacing a matrix column with a vector May 4 revised Computing the complex integral? deleted 1 character in body Apr 13 comment Calculate $\int_\Gamma ze^{z}dz$ where $\Gamma$ is line from point $z_1=0$ to point $z_2=\frac{\pi i}{2}$ @user227317 yes. See my answer for full details, but you got the answer! You can also use Blatter's approach too. Apr 13 answered Calculate $\int_\Gamma ze^{z}dz$ where $\Gamma$ is line from point $z_1=0$ to point $z_2=\frac{\pi i}{2}$ Apr 12 comment Calculate $\int_\Gamma ze^{z}dz$ where $\Gamma$ is line from point $z_1=0$ to point $z_2=\frac{\pi i}{2}$ @user227317 no, as I said use the substitution $z=it$. Also @ JessicaK's solution will also work. See also @ ChrisrianBlatter's answer. Apr 12 comment Calculate $\int_\Gamma ze^{z}dz$ where $\Gamma$ is line from point $z_1=0$ to point $z_2=\frac{\pi i}{2}$ You need to parametrize the curve $\Gamma$, e.g. let $z(t)=it$ where $t\in[0,\pi/2]$. Looks like integration by parts may be helpful too. Apr 11 revised Calculating the lie algebra of $SO(2,1)$ added 1 character in body Apr 8 comment $F(x)+G(y)= e^{x+y}?$ Yes, the way it is written confused me for a moment. However, on expanding the middle equality now I clearly see it does equal $F(1)-F(0)$. I was looking at what you had written from a different perspective - I was trying to construct the middle equality from the first by rearranging the original equation. Sorted now I see clearly what's happing - that "old trick" of adding something and then taking it away, so yes maybe best read right to left. +1 for your answer! Apr 8 comment $F(x)+G(y)= e^{x+y}?$ I could be wrong, but shouldn't the middle equality be $-G(y)+e^{1+y}-(-G(y)+e^y)$ ? Maybe it's equivalent... Apr 8 revised How to deduce that $1\cdot 1 + 2\cdot 1 + 2\cdot 2 + 3\cdot 1+3\cdot 2+3\cdot 3 +…+(n\cdot n) = n(n+1)(n+2)(3n+1)/24$ edited title Apr 8 revised How to deduce that $1\cdot 1 + 2\cdot 1 + 2\cdot 2 + 3\cdot 1+3\cdot 2+3\cdot 3 +…+(n\cdot n) = n(n+1)(n+2)(3n+1)/24$ added 18 characters in body Apr 8 comment How to deduce that $1\cdot 1 + 2\cdot 1 + 2\cdot 2 + 3\cdot 1+3\cdot 2+3\cdot 3 +…+(n\cdot n) = n(n+1)(n+2)(3n+1)/24$ Try proof by induction ?