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Q&A Meta

Posts by Derek Elkins‭

50 posts
Score Age
71%
+3 −0
Q&A Find the value of $\sum_{k=1}^\infty\frac{k^2}{k!}$

posted 8mo ago by Derek Elkins‭

Answer
71%
+3 −0
Q&A Are we in a "history-valley" for Topology?

posted 3y ago by Derek Elkins‭

Answer
71%
+3 −0
Q&A Maximize Independent Variable of Matrix Multiplication

posted 3y ago by Derek Elkins‭

Answer
71%
+3 −0
Q&A Show that $f(x) = \arctan\left(\frac{x}{x+1}\right) + \arctan\left(\frac{x+1}{x}\right) = \frac{\pi}{2}$

posted 2y ago by Derek Elkins‭  ·  edited 2y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A The meaning of $\pm$

posted 2y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Why $\gamma\cdot\operatorname{grad}u<0$ in the Theorem? (Nirenberg academic paper)

posted 7mo ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Interpreting $\text{Prop}$ in Set

posted 10mo ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Intuitively, why doesn't picking unpopular integers ($> 31$) lower your probability of winning lotteries?

posted 1y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A how to mathematically express a relationship in which a vector can be any 3D unit vector

posted 2y ago by Derek Elkins‭  ·  edited 2y ago by trichoplax‭

Answer
66%
+2 −0
Q&A Finding a single row of Matrix after exponentiation

posted 2y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Proving $|{\bf R}^{\bf R}|=|2^{\bf R}|$ using the Schroeder-Bernstein Theorem

posted 2y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Are vectrices useful for calculations as opposed to formalism?

posted 3y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Is Pythagorean theorem really valid in higher dimensional space?

posted 3y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A Getting backward of partial differentiation's chain rule

posted 3y ago by Derek Elkins‭  ·  edited 3y ago by Derek Elkins‭

Answer
66%
+2 −0
Q&A methodology of integration by parts ($e^{ax}\cos (bx+c)\mathrm dx$)

posted 3y ago by Derek Elkins‭  ·  edited 3y ago by r~~‭

Answer
60%
+1 −0
Q&A Unification and generalization of limit and colimit

posted 2y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A How to derive some trigonometric formulas?

posted 3y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A The purpose of logical frameworks in specifying type theories

posted 2y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A On Tarski-style universes in type theory

posted 2y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A Acceptable, usual to write $\ge 2$ pipes simultaneously?

posted 3y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A $\int dx dy dz d p_x dp_y dp_z$ Does it have any physical meaning?

posted 3y ago by Derek Elkins‭  ·  edited 3y ago by r~~‭

Answer
60%
+1 −0
Q&A $\sup(A\cdot B) = (\sup A)(\sup B)$ where $A$ and $B$ bounded sets of positive real numbers

posted 1y ago by Derek Elkins‭  ·  edited 1y ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A Is there a $\Delta$-complex structure on the sphere with less than three $0$-simplices?

posted 12mo ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A Complex functions and inner product $\langle \frac{\partial f}{\partial z} , g\rangle $

posted 8mo ago by Derek Elkins‭

Answer
60%
+1 −0
Q&A Reflection in the plane with polar coordinates

posted 7mo ago by Derek Elkins‭  ·  edited 7mo ago by Derek Elkins‭

Answer