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Interesting 5 Bountied Hot Week Month
6 votes
4 answers
426 views

If $a,b,c>0$ such that $(a+b+c)^3=125abc$, then show that $ \dfrac{a}{\sqrt{bc}}+\dfrac{b}{\sqrt{ca}}+\dfrac{c}{\sqrt{ab}} \le \dfrac{16+\sqrt{2}}{2}$

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John Bentin
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7 answers
211 views

Cleanest way to prove $\frac{\sin x}{1-\cos x} + \frac{1-\cos x}{\sin x} = \frac{2}{\sin x}$

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Taladris
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0 answers
4 views

Invariant Hermitian form for a so(5)-module

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0 answers
8 views

Collinearity involving Napoleon points, Fermat points, and the nine-point center

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زكريا حسناوي
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1 answer
615 views

Homework solving exponential equation, logarithmic equation and exponential equation.

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0 answers
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Prove $x^x + x^y + y^x + y^y > 2 + \exp(-1/e)$ for $x, y > 0$

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Martin R
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4 votes
2 answers
296 views

What is the etymology of the mathematical use of the word "regression"?

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0 answers
20 views

Why isn’t Var(X) just the average of Var(X|Y)?

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Kakashi
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1 answer
115 views

Simplifying $\sum_{k=1}^n\frac{x^k}{k!}$

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Claude Leibovici
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1 answer
324 views

Is $x^2$ uniformly continuous on $\mathbb{R}$?

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Anne Bauval
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1 vote
1 answer
631 views

Find the Taylor series of $f(x) =\sqrt{1 + \sin{x}}$ around $x_0= 0$

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1 vote
2 answers
97 views

Showing that the set of linear mappings from a finite-dimensional vector space to an infinite-dimensional vector space is infinite-dimensional

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s114
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1 answer
270 views
+50

What values $\deg(Q)$ can take?

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Precipitation
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0 answers
35 views

Forward half-gap parameterization of primes — is this viewpoint known?

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Eric Towers
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3 votes
2 answers
86 views

Reflections of a point with respect to the sides of a triangle lie on a conic passing through the triangle’s vertices

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Blue
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0 answers
25 views

Proving $A\vec{x}=\vec{b}$ has a solution iff $A^{T}\vec{x}= \vec{0}$ has the trivial solution.

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0 answers
74 views

Determining if a transformation from polynomials to infinite sequences is an isomorphism

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Anne Bauval
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0 answers
9 views

General formula for the normal bundle of strict transform

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Calculus101
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4 votes
7 answers
372 views

Finding the minimum value $f(x)=x^2+\frac{2}{x}$, $x \gt 0$

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Игорь
  • 1,385
3 votes
2 answers
590 views

Suppose $V$ is finite-dimensional. Show that the only two-sided ideals of $\mathcal{L}(V)$ are $\{0\}$ and $\mathcal{L}(V)$. (From Axler's book.)

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s114
  • 501
2 votes
1 answer
614 views

About the proof of the Lindeberg-Feller theorem.

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2 votes
1 answer
228 views

Tensor product classifies cooperating arrows?

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Vladimir Sotirov
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1 answer
619 views

Frobenius method to solve differential equations, different \alpha found

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8 votes
18 answers
2k views

What is $0\div0\cdot0$?

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Precipitation
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3 votes
2 answers
282 views

Simple Integral Involving the Square of the Elliptic Integral

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Shreyash Pachore
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4 votes
1 answer
622 views

Relation between RKHS and space of continuous functions

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1 answer
44 views

How to Change the Velocity of a Vector Function?

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Oğuzhan Kılıç
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9 votes
3 answers
429 views

If $xy+x$ and $xy+y$ are squares, for positive integers $x$ and $y$, then ...

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David E Speyer
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1 vote
1 answer
58 views

Existence of periodic solution of a 2nd order homogeneous ODE

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Gonçalo
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6 votes
3 answers
287 views

How to calculate $\int_{0}^{2\pi}\frac{\sin^{2}k}{(1+a\cos k)\sqrt{1+b\cos k}}dk$ (elliptic integral)?

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Dibakoane Lancelot
  • 163
0 votes
1 answer
61 views

Showing that the sum of positive terms is divergent for an absolutely divergent but conditionally convergent series

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TonyK
  • 68.9k
-1 votes
1 answer
30 views

Compare the singular values with diagonal elements for a upper triangular matrix

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Precipitation
  • 19
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1 answer
626 views

Determining whether a critical point is max,min or saddle

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5 votes
5 answers
429 views

Prove $(a^2+b^2+c^2)^3 \ge 9(a^3+b^3+c^3)$

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A rural reader
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2 answers
79 views

Struggling for count of maximum subset

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Mike Earnest
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1 vote
0 answers
28 views

Does the ABC Conjecture Imply an Extension of the ABC Conjecture to $n$ Variables

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1 answer
54 views

What is an ellipse-factor in Linear Algebra?

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1 answer
762 views

Formally proving Unitary Matrices as Product of matrices

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51 views

Does every stable class in a persistence module over a filtered measure space with $\rho > 0$ necessarily map to zero at $\rho = 0$?

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51 views

Is it true that a finite $2$-group containing exactly three involutions, is $2$ generated?

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TShiong
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1 vote
1 answer
79 views

Does there exist a database for Dirichlet $L$-series?

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Gonçalo
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3 votes
1 answer
180 views

Partial Fraction Decomposition in Complex Analysis

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0 answers
47 views

Rewriting with arcsinh in Atkinson's formula for mean value of $\zeta$-function

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TShiong
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2 votes
1 answer
100 views

Hint needed, iteratively applying linear map

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TShiong
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1 vote
1 answer
138 views

On Evaluating $\lim\limits_{x \to \pi^-} \sum_{n=1}^\infty\frac{2(-1)^{n+1}}{n}\sin nx$

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0 answers
48 views

Prob. 9, Sec. 30, in Munkres' TOPOLOGY, 2nd ed: A closed subspace of a separable space need not be separable

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0 answers
24 views

Bass Serre theory references

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timoselvatico
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1 vote
1 answer
112 views

Can the definition of a T1 space be simplified?

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J. W. Tanner
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8 votes
4 answers
8k views

What's the opposite of damping?

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Vinyasi
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0 answers
29 views

Understanding How to Get From Subgroups of Galois Group to Normal, Abelian Quotients

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Lucien Jaccon
  • 1,356
6 votes
1 answer
1k views

High-order antiderivatives of the Weierstrass $\wp$-function

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46 votes
7 answers
14k views

Geometric explanation of $\sqrt 2 + \sqrt 3 \approx \pi$

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vallev
  • 1,297
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0 answers
15 views

Do Morse functions having a local maximum/minimum exist on any manifold?

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Ishan Deo
  • 4,097
3 votes
3 answers
300 views

A beautiful heart-shaped curve generated from an ellipse and a circle

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Jean Marie
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6 votes
0 answers
103 views

Is there a good set with degree $3$?

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Salmon
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2 votes
2 answers
625 views

When can one extend a function on the unit circle to an analytic function?

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7 votes
2 answers
220 views

Analytic solution of the $3\times3$ symmetrical ODE system $x'_i=-x_i\cdot(x_i-\bar{x})$

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Cesareo
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3 votes
2 answers
119 views

PDE textbooks and interpretations

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Giuseppe Negro
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9 votes
1 answer
3k views

Why is the "Buffalo Way" considered inelegant?

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Semiclassical
  • 20k
0 votes
3 answers
167 views

Binary Transmission Protocols

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Semiclassical
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2 votes
2 answers
2k views

The line graph of Eulerian and Hamiltonian graphs

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Isaac Tung
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3 votes
1 answer
240 views

Did Vitali put an end to Lebesgue's measure problem?

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Mikhail Katz
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4 votes
1 answer
788 views

Identity for the divisor function: $\tau(mn)=\sum\limits_{d\mid(m,n)}\mu(d) \tau(m/d)\tau(n/d)$

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1 vote
1 answer
54 views

How do I characterize the inverse of this corestriction?

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Nate
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1 vote
1 answer
97 views

$12$ rays in plane inducing a trigonometric inequality

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mezzoctane
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0 answers
35 views

Extremal values of $\sum_{cyc}\cos^{-1}\left(\frac{\cos\gamma_1+\cos\gamma_2\cos\gamma_3}{\sin\gamma_2\sin\gamma_3}\right)$, with $0<\gamma_i<\pi$

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Allium tuberosum
  • 153
1 vote
1 answer
623 views

Conditional Expectation under Transformation of Variables

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8 votes
3 answers
216 views

Find the range of $a$ such that there exists a line having no intersection with $2\cos x−\cos y=a$

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David K
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0 votes
2 answers
55 views

Monotonicity in $\kappa$ of the algebraic comparison-angle formula

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Allium tuberosum
  • 153
1 vote
1 answer
114 views

Clarify on a fact about exact triangles and $t$-structures

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Ben Steffan
  • 14k
3 votes
1 answer
170 views

Does a functor between semiadditive categories preserve finite products if and only if it preserves coproducts?

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Stanis LaRochelle
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7 votes
2 answers
189 views

Determining Expected value of dice roll with unknown number of sides.

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Michael
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1 vote
2 answers
80 views

Morphism of $k$-schemes: Enough for the map of global sections to be $k$-algebra homomorphism?

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Lukas Heger
  • 27.8k
5 votes
2 answers
249 views

Maximal Ideals of $K[x_1,x_2,...,x_n]$

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Stanis LaRochelle
  • 764
1 vote
1 answer
78 views

opposite angles of a quadrilateral are congruent

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Kulisty
  • 1,834
1 vote
1 answer
620 views

Resolution method: example

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CommunityBot
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1 vote
1 answer
107 views

the numbers of lines is greater than or equal to the number of points

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Kulisty
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0 answers
304 views

$(a^2+b^2+c^2)^2 \ge 3(a^3b+b^3c+c^3a)$

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user26857
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0 answers
39 views

Exercise about matrix representation in quadratic space

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Sammy Black
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3 votes
1 answer
193 views

$A$ is onto iff $AA^*$ is bounded below.

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user8675309
  • 13.2k
5 votes
3 answers
915 views

Product of the digits of an integer $n$

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tabi_the_dup
  • 169
3 votes
0 answers
62 views

Noetherian local ring that is not catenary (Nagata's example)

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why
  • 375
1 vote
1 answer
744 views

Surface area of a sphere above a cone

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1 vote
1 answer
631 views

Approximating the integral of the exponential of a quadratic function

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1 vote
0 answers
39 views

Oscillatory integral with amplitude 1

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N230899
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1 vote
2 answers
4k views

Partial derivative in gradient descent for logistic regression

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Myungheon Lee
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9 votes
1 answer
256 views

Perfect squares of the form $n^m+m^n$

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MCipu
  • 420
1 vote
0 answers
24 views

CLRS exercise: Upper bounding number of right rotations to transform a binary tree

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youthdoo
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88 votes
12 answers
39k views

What are the applications of functional analysis?

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Lee Mosher
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4 votes
0 answers
104 views

Coloring the sphere mod 3?

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GaussJordan
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33 votes
6 answers
7k views

Simply connected manifolds are orientable

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Allium tuberosum
  • 153
4 votes
0 answers
120 views

Uses of the Yoneda lemma in its full power

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Baylee V
  • 1,057
6 votes
8 answers
2k views

find the minimum value given constraints

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Nate
  • 1,247
4 votes
2 answers
135 views

Is the intersection of base fields of two normal extensions again normal?

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Martin Brandenburg
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3 votes
1 answer
74 views

$G$ is a finite $2$-group containing exactly $3$ involutions with only one having square root. Does it imply that $G^2$ contains unique involution?

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HackR
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1 answer
2k views

Write an equation of a linear relation representing this scenario.

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