Michael Albanese
Reputation
32,660
91/100 score
 3h answered If an $n\times n$ matrix $A$ is diagonalizable and has only one eigenvalue $\lambda$ with multiplicity $n$, then $A = \lambda I$. True or False? 7h comment How to prove the following identity? 8h comment Is every point in the set defining some curve or line in $\mathbb{C}$ or $\mathbb{R}$ a boundary point? @RobArthan: My answer addresses the question that was initially asked. The OP edited the question an hour ago and added the simple hypothesis; note that my answer was submitted well before that. 9h comment Taking the derivative of a matrix multiplied by a vector In your definition, do you mean an $m\times n$ matrix? 10h comment Write the vector field such that its integral curves are the meridians of $S^2$ Note that \cos produces $\cos$ as opposed to cos which produces $cos$. 10h revised Figure out attendance needed for remaining days to reach attendance goal edited tags 10h comment Taking the derivative of a matrix multiplied by a vector What definition of derivative are you using? 16h awarded Enlightened 22h awarded Revival 22h reviewed Close Real Analysis Differentiating under the integral 22h reviewed Close linear algebra: deciding if this is a vector space over R? 23h revised Find a $4\times 4$ matrix whose reduced row echelon form has two leading ones and whose row space intersects its column space only at the origin. edited tags 1d awarded Good Answer 1d awarded Good Answer 1d revised Do two closed subsets of $[0, 1]$ with measure $\frac{1}{2}$ intersect? rolled back to a previous revision 1d comment Are there rings whose multiplicative identity is not the number 1 or number 1-based? @GerryMyerson: The example is the same, but we answered only minutes apart. 1d comment Functional equation and algebra This should be a comment on Yiorgos S. Smyrlis' answer, not a separate question. 1d revised Riemann integrable proof? added 98 characters in body 1d comment Riemann integrable proof? Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level. 1d awarded Nice Answer