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Q&A Meta

Posts by Derek Elkins‭

49 posts
Score Age
85%
+10 −0
Q&A Complex numbers in 2D, quaternions in 4D, why nothing in 3D?

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

Answer
81%
+7 −0
Q&A What is the Name of Function for Probability of a Certain Sum on Random Die Rolls?

posted 2y ago by Derek Elkins‭

Answer
81%
+7 −0
Q&A Does every divergence-free vector field arise as the curl of some vector field?

posted 4y ago by Derek Elkins‭  ·  edited 3y ago by Derek Elkins‭

Answer
80%
+6 −0
Q&A Existence of a set of all sets

posted 4y ago by Derek Elkins‭  ·  edited 4y ago by Derek Elkins‭

Answer
80%
+6 −0
Q&A Average distance from circle's center to a point

posted 1y ago by Derek Elkins‭  ·  edited 1y ago by TheCodidacter, or rather ACodidacter‭

Answer
80%
+6 −0
Q&A Why does “unless” mean “if not”?

posted 4y ago by Derek Elkins‭

Answer
77%
+5 −0
Meta Can this site contains Physics's Math question?

posted 3y ago by Derek Elkins‭

Answer
77%
+5 −0
Q&A What're the orders for equation expressing?

posted 3y ago by Derek Elkins‭

Answer
77%
+5 −0
Q&A Why always rationalize a denominator?

posted 4y ago by Derek Elkins‭

Answer
75%
+7 −1
Meta Marketing Math Codidact

1 answer  ·  posted 4y ago by Derek Elkins‭  ·  last activity 4y ago by The Amplitwist‭

Question discussion
75%
+4 −0
Q&A Why does the method of separating variables work?

posted 6mo ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A How to find a point on a vector equation with another vector equation and perpendicular distance?

posted 6mo ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A Prove that $\forall x\in\Bbb R:\lfloor x^2\rfloor-\lfloor rx\rfloor\ge-1\iff|r|\le2$.

posted 8mo ago by Derek Elkins‭  ·  edited 8mo ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A Picture proof for expansion of $x^n−y^n$

posted 1y ago by Derek Elkins‭

Answer
75%
+4 −0
Meta Should posting on Meta affect reputation?

posted 1y ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A Can we constructively find a third element of a set $X$ satisfying $X \cong X \times X$ given two distinct elements?

0 answers  ·  posted 4y ago by Derek Elkins‭

Question constructive-logic type-theory
75%
+4 −0
Q&A Proving that $p\mid (p+1776)$ if $p$ is a prime and $p(p+1776)$ is a perfect square

posted 2y ago by Derek Elkins‭

Answer
75%
+4 −0
Meta Are challenge-like questions like these considered on-scope in Mathematics CD?

posted 3y ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A What was Justice Scalia's mathematical mistake in Penry v. Lynaugh (1989)?

posted 3y ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A How to show if a set is simply connected?

posted 3y ago by Derek Elkins‭

Answer
75%
+4 −0
Q&A Why does this definition of generalized forces work?

posted 4y ago by Derek Elkins‭

Answer
71%
+3 −0
Q&A Generalization of categorical product

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

Answer
71%
+3 −0
Q&A Prove $e^x \ge x+1 \\\; \forall x \in \mathbb{R}$ using induction

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

posted 4mo ago by Derek Elkins‭

Answer