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4

votes

2

answers

159

views

How can I define the intersection area of an ellipse and a circle?

integration geometry circles area

modified 1 min ago Jan Eerland 25k

0

votes

0

answers

5

views

How to prove this is a norm

real-analysis functional-analysis analysis norm

asked 2 mins ago delta 29

0

votes

1

answer

17

views

Triangle of maximal area with vertices origin and intersections of a chord with a curve

calculus

answered 3 mins ago g.kov 9,449

0

votes

0

answers

11

views

How to prove $-|a|\le a\le |a|$ based on the fact that $|a|\le b ⇔ -b\le a\le b$

algebra-precalculus

asked 4 mins ago Richard 85

0

votes

1

answer

17

views

About differential equations

derivatives

answered 4 mins ago Deep Fry 11

1

vote

2

answers

14

views

How would one go about Laplace Transforming $\max(0, \sin(t))$?

complex-analysis laplace-transform

answered 5 mins ago Stratiev 56

0

votes

0

answers

7

views

Product of a matrix and its transpose is doubly stochastic?

matrices matrix-calculus

asked 5 mins ago slm992 17

0

votes

1

answer

11

views

Continuity and the definition of a function.

algebra-precalculus limits continuity

answered 6 mins ago Yves Daoust 170k

1

vote

1

answer

15

views

Intuition of conjugacy in symmetry groups

group-theory intuition

answered 7 mins ago runway44 4,192

0

votes

2

answers

25

views

Resolution of a limit

analysis

answered 8 mins ago Yves Daoust 170k

0

votes

0

answers

8

views

Bijection between $\mathbb{Z}/ m\mathbb{Z}$ and the set of elements coprime to all divisors of $m$

elementary-number-theory

asked 8 mins ago 3891780 431

0

votes

1

answer

29

views

Convergence in $L^1$ implies uniform integrability

probability-theory

modified 9 mins ago Kavi Rama Murthy 191k

0

votes

0

answers

4

views

Why is the Laplace transform usually defined to be conditionally convergent?

laplace-transform

asked 10 mins ago ogogmad 7,313

1

vote

0

answers

16

views

Help for a proof with orthogonal unit vectors

linear-algebra matrices vector-spaces eigenvalues-eigenvectors orthogonality

modified 11 mins ago DanteAligante 11

0

votes

2

answers

18

views

Computation of the integral $\int_0^{\infty} \frac{x^2}{(a^2-x^2)^2-x^2b^2}dx$

calculus integration definite-integrals

answered 11 mins ago Harish Chandra Rajpoot 32.7k

0

votes

0

answers

2

views

Obtaining the Bonferroni 95% confidence intervals of my regression coefficients

confidence-interval

asked 12 mins ago Ahmed Abdulla 1

0

votes

1

answer

13

views

On the use of Weierstrass' M-test for uniform convergence of series including unbounded terms

real-analysis analysis

answered 14 mins ago Kavi Rama Murthy 191k

0

votes

0

answers

8

views

Homogeneous coordinates of a line in the projective plane

geometry projective-geometry projective-space

modified 14 mins ago user735782 101

0

votes

0

answers

11

views

How to prove the degrees of freedom is N(N-1)/2

statistics

asked 14 mins ago Nikki 19

1

vote

1

answer

11

views

Convert the given Boolean function into its $NOR$ Normal Form.

functions discrete-mathematics logic boolean-algebra

modified 14 mins ago Ski Mask 1,096

0

votes

0

answers

6

views

How to argue if implicit function theorem fails that there exist no function?

real-analysis calculus multivariable-calculus

asked 17 mins ago MathLover 3,987

0

votes

0

answers

14

views

The sup of square of root P which P is a constant

real-analysis analysis

modified 17 mins ago Bernard 148k

0

votes

0

answers

6

views

Show that $X_n$ converges in distribution to $X$ if and only if $\lim_{n→∞} P(X_n = k) = P(X = k)$

probability probability-distributions convergence-divergence

asked 20 mins ago user13 1,312

2

votes

2

answers

31

views

Prove that there are infinitely many integers that are not of the form $n^3+2m^2$ for integers $m,n$. (Hint: Consider the situation modulo 8).

elementary-number-theory modular-arithmetic

answered 21 mins ago DanielWainfleet 43.6k

0

votes

0

answers

6

views

Prove that $\int\sum k\chi_{f^-1}<\infty$

measure-theory lebesgue-integral lebesgue-measure measurable-functions measurable-sets

asked 22 mins ago Alejandro Bergasa Alonso 402

0

votes

1

answer

18

views

Block matrix determinant property(sum)

matrices determinant block-matrices

modified 23 mins ago Rodrigo de Azevedo 15.3k

4

votes

2

answers

819

views

Rotman Introduction to Algebraic Topology Question 0.5

algebraic-topology

answered 24 mins ago Herlin 1

0

votes

1

answer

15

views

Accuracy of low rank approximation

matrices optimization matrix-decomposition matrix-rank

modified 24 mins ago Rodrigo de Azevedo 15.3k

0

votes

0

answers

6

views

Condition number of normalized matrices

matrices condition-number

modified 27 mins ago Rodrigo de Azevedo 15.3k

0

votes

0

answers

9

views

Single-valued enumeration of all c.e. sets

computability

modified 28 mins ago T uS 1

0

votes

1

answer

10

views

Differential Equations

derivatives

29 mins ago Naruto 1

0

votes

0

answers

8

views

How do you solve the differential equation dvx/dt = Cvy where vx and vy are the x and y component of velocity and C is a constant

calculus

asked 29 mins ago zopxm 11

0

votes

1

answer

18

views

Inverting symmetric matrix

matrices inverse symmetric-matrices

answered 29 mins ago user1551 95k

0

votes

0

answers

3

views

Limit involving the regularized incomplete beta function

real-analysis limits probability-distributions

asked 30 mins ago Vuk 163

1

vote

0

answers

24

views

Given the point $T$ and the line $p$, find the distance between their orthogonal projections onto the plane $\pi$.

geometry vectors analytic-geometry solution-verification

modified 31 mins ago Cheesecake 4,452

0

votes

0

answers

5

views

Equivalence in strong convergence of operators

operator-theory banach-spaces

asked 32 mins ago Something 1,767

0

votes

0

answers

8

views

Pairing probability (high school maths problem)

probability

asked 33 mins ago BooScout 169

0

votes

1

answer

14

views

What is wrong with my answer to the question below?

volume

answered 33 mins ago Harish Chandra Rajpoot 32.7k

0

votes

0

answers

3

views

Calculate percentage based on specific 0% and 100% in any numeric range

percentages

asked 37 mins ago SharpShade 101

3

votes

0

answers

22

views

Maximum ellipse inscribed in Witch of Agnesi curve

calculus geometry

modified 38 mins ago Ninad Munshi 12.3k

2

votes

1

answer

26

views

Polynomial-Exponential Equation

real-analysis sequences-and-series polynomials exponential-function

answered 39 mins ago p4sch 6,770

0

votes

0

answers

15

views

Show that a set of complex functions is finite

calculus complex-analysis

modified 39 mins ago Igor 89

0

votes

0

answers

4

views

Confidence interval $N(\theta,\theta)$

normal-distribution confidence-interval

asked 41 mins ago Le_Poisson 11

0

votes

0

answers

4

views

Derivatives of surface curvature

differential-geometry curvature

asked 42 mins ago Museful 685

1

vote

1

answer

14

views

Cartesian product of Kolmogorow spaces is also Kolmogorov space

general-topology

answered 44 mins ago mathcounterexamples.net 37.5k

0

votes

1

answer

18

views

Reference request: convergence for periodic Markov chains

reference-request markov-chains

modified 46 mins ago user8675309 2,044

3

votes

1

answer

30

views

Is it true that for jordan block with zero eigenvalue we can choose basis where all diagonal elements are non zero?

linear-algebra jordan-normal-form

answered 48 mins ago Fabrizio 213

2

votes

2

answers

29

views

Restriction of surjective linear map is isomorphism

linear-algebra

modified 48 mins ago Bernard 148k

3

votes

0

answers

32

views

+50

Getting Rotation Matrix Using 3-Point Calibration

coordinate-systems symmetric-matrices

modified 49 mins ago Moayad Hani Abu Rmilah 81

1

vote

1

answer

9

views

Magnitudes of odds ratio and relative risk similar, what does this mean?

probability statistics

modified 49 mins ago StubbornAtom 11.1k

0

votes

2

answers

43

views

Finding isomorphism between two groups

group-theory group-isomorphism group-homomorphism quotient-group

modified 49 mins ago user750041 893

2

votes

1

answer

13

views

Does the integral of a function exist at a sharp point in the function?

functions

answered 52 mins ago csch2 2,494

0

votes

0

answers

5

views

Finite propagation speed of strictly hyperbolic equation

partial-differential-equations hyperbolic-equations linear-pde cauchy-problem

asked 56 mins ago WWC220023 1

3

votes

2

answers

1k

views

Another form of the Sandwich theorem (for derivatives in dimension $1$)

real-analysis proof-verification

modified 56 mins ago Community♦ 1

0

votes

1

answer

13

views

A question based on lower limit topology( 2nd countable, 1st countable)

general-topology analysis

modified 57 mins ago Kevin. S 1,477

0

votes

1

answer

19

views

Spivak Calculus chapter 1 question 14

algebra-precalculus proof-writing

answered 57 mins ago James 3,451

0

votes

0

answers

7

views

saddle point method with conjugate complex roots

asymptotics physics education statistical-mechanics large-deviation-theory

modified 58 mins ago user784507 1

0

votes

2

answers

25

views

Prove that if $\lambda$ is an eigenvalue of a linear map $f$ then $(\lambda +i)(\lambda -i)^{-1}$ is the eigenvalue of another linear map $g$

linear-algebra vector-spaces eigenvalues-eigenvectors linear-transformations inner-product-space

modified 59 mins ago darij grinberg 14.1k

1

vote

1

answer

33

views

Proving the map $f-i\cdot \text{id}_v$ is invertible with $f:V\to V$ a self-adjoint linear map

linear-algebra vector-spaces linear-transformations inner-product-space adjoint-operators

modified 1 hour ago darij grinberg 14.1k

0

votes

0

answers

9

views

prove integrable functions by means of Holder inequality

integration holder-inequality

asked 1 hour ago majid 81

0

votes

0

answers

8

views

exact sequence of sheaves extended by zero

algebraic-geometry

asked 1 hour ago Yu Ning 141

1

vote

1

answer

30

views

Rate convergence to fixed point of a function

fixed-point-theorems fixed-points

modified 1 hour ago Yves Daoust 170k

0

votes

1

answer

26

views

Sufficient statistic by factorization theorem

statistics probability-distributions statistical-inference log-likelihood data-sufficiency

modified 1 hour ago StubbornAtom 11.1k

0

votes

2

answers

16

views

Complement of multiplicative set is a (prime) ideal.

ideals

answered 1 hour ago Shivering Soldier 9,367

3

votes

1

answer

101

views

+50

Can convolution be expressed as a differential equation?

calculus ordinary-differential-equations convolution

answered 1 hour ago user619894 1,414

0

votes

0

answers

10

views

Euclidean geometry- how do I finish this proof

contest-math euclidean-geometry

asked 1 hour ago MNIShaurya 480

3

votes

0

answers

45

views

Prove that bounded function with midpoint convex is continuous

calculus continuity jensen-inequality

modified 1 hour ago ToBY 840

0

votes

0

answers

17

views

Issue with cylindrical integration

integration multivariable-calculus cylindrical-coordinates

asked 1 hour ago Charles Cooper 25

3

votes

1

answer

33

views

Number of $2 \times 2$ matrices over the finite field $\mathbb{F}_q$ whose minimal polynomial is divisible by $X-1$.

linear-algebra matrices vector-spaces linear-transformations finite-fields

modified 1 hour ago user26857 41.7k

0

votes

0

answers

26

views

Depth of $i$-th syzygy module, where $i$ is at most the depth of the ring

commutative-algebra homological-algebra

modified 1 hour ago user26857 41.7k

1

vote

0

answers

10

views

Comparing explicit generators of the $n$-th singular homology group of $S^n$.

algebraic-topology homology-cohomology

asked 1 hour ago Colescu 6,663

1

vote

0

answers

11

views

Lipschitz by Stone-Weierstrass

analysis holder-spaces weierstrass-approximation

asked 1 hour ago defenestrator 416

4

votes

1

answer

56

views

+50

Find shortest path in undirected complete n-partite graph that visits each partition exactly once

graph-theory algorithms

answered 1 hour ago Alex Ravsky 59.2k

-1

votes

0

answers

11

views

$SL_4(\mathbb R)$ as a subgroup of $SL_3(\mathbb C)$

group-theory lie-groups lie-algebras algebraic-groups

asked 1 hour ago June 61

0

votes

0

answers

18

views

Flux through cone revisited

multivariable-calculus vector-analysis vector-fields divergence-theorem

modified 1 hour ago Peter 118

3

votes

0

answers

36

views

Questions about cohomology and cocycles in Munkres's book and my attempt to find cocycles in $n$-fold dunce cap

algebraic-topology solution-verification homology-cohomology

modified 1 hour ago Kevin. S 1,477

1

vote

0

answers

11

views

A question related to tensor product of $R$-modules

abstract-algebra ring-theory modules tensor-products flatness

modified 1 hour ago Sumanta 3,667

0

votes

0

answers

8

views

test spaces and variational formulation in finite elements for elliptic problems

sobolev-spaces boundary-value-problem weak-derivatives finite-element-method

modified 1 hour ago giorgio pulvirenti 1

0

votes

0

answers

24

views

find points close to targets, but at least min_dist apart

optimization convex-optimization

modified 1 hour ago Nico Schlömer 824

0

votes

0

answers

10

views

A compact hyperbolic manifold and fundmental group

differential-geometry hyperbolic-geometry fundamental-groups

asked 1 hour ago Chern 1

0

votes

0

answers

20

views

N Balls in two urns

probability conditional-probability balls-in-bins

asked 1 hour ago Francesco Totti 53

-1

votes

0

answers

14

views

Density of tensor products of eventually zero sequences.

real-analysis sequences-and-series functional-analysis

modified 1 hour ago Prof.Hijibiji 184

0

votes

0

answers

18

views

The boundedness of a determinant

linear-algebra determinant

asked 1 hour ago ling 757

7

votes

0

answers

132

views

+500

How to utilize the special feature of this recursive problem to reduce computational complexity?

reference-request algorithms matrix-equations numerical-linear-algebra recursive-algorithms

modified 2 hours ago LAD 5,386

2

votes

1

answer

19

views

$A \subset B$ be a faithfully flat extension of domains and $B$ is integrally closed then $A$ is also integrally closed.

commutative-algebra flatness integral-extensions

answered 2 hours ago Youngsu 2,591

0

votes

0

answers

16

views

Prove that M is a martingale

stochastic-processes stochastic-calculus martingales local-martingales

asked 2 hours ago Ivan Petrov 1

3

votes

0

answers

24

views

Is the Cesàro sum of the Fourier series of $f$ a best approximation of $f$ in any sense?

soft-question fourier-analysis harmonic-analysis summation-method cesaro-summable

modified 2 hours ago Bob 3,488

1

vote

2

answers

27

views

Evaluate $\lim_{n \to \infty} \sum_{j=0}^{n} \sum_{i=0}^j \frac{i^2+j^2}{n^4+ijn^2}$

calculus integration summation riemann-sum direct-sum

answered 2 hours ago J.G. 74.5k

0

votes

0

answers

11

views

Find the maximum of piece-wise multivariate function?

multivariable-calculus optimization piecewise-continuity

asked 2 hours ago Cong 3

2

votes

1

answer

18

views

Unit of a monoid object in a monoidal category

abstract-algebra category-theory

answered 2 hours ago asdq 2,883

0

votes

1

answer

19

views

Variation of parameters: $y'''+y''=\csc x$

integration ordinary-differential-equations

modified 2 hours ago Sonal_sqrt 4,178

1

vote

0

answers

7

views

if such counter example to Lehmer's totient problem exists then could we have more counter examples?

arithmetic-functions primality-test lucas-lehmer-test

asked 2 hours ago zeraoulia rafik 5,899

0

votes

1

answer

24

views

given 9 consecutive naturals, no partition into two sets will give set one product = set two product

number-theory contest-math divisibility

answered 3 hours ago Haran 4,810

3

votes

1

answer

28

views

Ways to fill up a $4 \times 4$ matrix with numbers $1$ to $16$, s.t its rank is $1$ under modulo $17$

combinatorics generating-functions

answered 3 hours ago saulspatz 34.7k

0

votes

0

answers

20

views

Find the unknown angles at the equilibrium of surface tension vectors

trigonometry triangles solution-verification problem-solving angle

modified 3 hours ago newstudent 163

3

votes

1

answer

1k

views

How to define Surface Laplacian on the sphere with radius 1

multivariable-calculus differential-geometry

modified 3 hours ago Community♦ 1

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