Mathematics Stack Exchange

2

votes

0

answers

13

views

About morphisms to the direct sum of modules

abstract-algebra ring-theory modules projective-module

modified 3 mins ago rschwieb 111k

1

vote

1

answer

6

views

Show that the morphism $Spec\mathbb{Q}\to Spec\mathbb{Z}_{(p)}$ is etale

algebraic-geometry

answered 3 mins ago Arthur 132k

0

votes

0

answers

5

views

Do all equations in three variables represent a two-dimensional surface in $\mathbb{R}^3$?

3d surfaces

asked 4 mins ago K. Claesson 309

2

votes

2

answers

28

views

Calculate the value of $I(9)/I(3)$ when $I(m)=\int_{0}^{\pi}\ln\left(1-2m\cos(x)+m^2\right)\,dx$

definite-integrals

modified 4 mins ago Anurag A 28.4k

0

votes

0

answers

18

views

New number triangle?

number-theory discrete-mathematics

modified 4 mins ago FromTheoryToPractice 39

2

votes

0

answers

9

views

The Fundamental group of the circle from “Introduction to knot theory”, Ralph H. Fox (1)

general-topology algebraic-topology proof-explanation fundamental-groups knot-theory

asked 6 mins ago hopefully 380

0

votes

0

answers

2

views

Convergence rate of inverse power method (without shift)

convergence numerical-methods

asked 8 mins ago binaryBigInt 132

1

vote

0

answers

6

views

How to determine the range of a set of matricies under matrix multiplication?

linear-algebra abstract-algebra matrices

modified 8 mins ago Rodrigo de Azevedo 13.5k

-1

votes

3

answers

33

views

Derivative of Inverse Sine

calculus

modified 9 mins ago Hoppy 20

0

votes

0

answers

5

views

Are their formulas for calculating the intersects on a ternary plot when I only know the cartesian x,y.

trigonometry

asked 11 mins ago Barry Hamilton 101

0

votes

0

answers

23

views

Can I use Gauss Elimination if one of my rows is full of 1?

linear-algebra matrices gaussian-elimination

modified 13 mins ago Rodrigo de Azevedo 13.5k

0

votes

0

answers

5

views

Special automorphism of the quaternionic structure

linear-algebra quaternions

asked 14 mins ago Dog_69 730

0

votes

1

answer

7

views

What's the difference between modal and epistemic logic?

answered 17 mins ago Noah Schweber 134k

1

vote

1

answer

32

views

Smooth function whose zeros cannot be computed

real-analysis logic

answered 19 mins ago Maciej Ficek 32

0

votes

0

answers

17

views

Expected number of calls for a Bingo win

probability recreational-mathematics

modified 20 mins ago JMoravitz 51.5k

1

vote

1

answer

24

views

Find an approximation for $ \int_0^1 f(x)\sqrt{x}dx \approx \omega f(x_1)$

integration numerical-methods approximation

modified 21 mins ago cmk 4,322

7

votes

1

answer

56

views

Study continuity of $f(x) = |x|$ for $x\in\Bbb R \setminus \Bbb Q$, $f(x) = \frac{qx}{q+1}$ for $x\in\Bbb Q$.

real-analysis calculus continuity

answered 24 mins ago quasi 37.8k

1

vote

1

answer

57

views

Computing probabilities by conditioning

probability probability-theory conditional-probability

answered 25 mins ago Markus Steiner 103

0

votes

1

answer

25

views

“Factor” a number into 1-16 products and sum parts

greatest-common-divisor

answered 28 mins ago user326210 10.7k

-2

votes

2

answers

139

views

Two Top Economist getting 9/10 correct

probability statistics

answered 36 mins ago Acccumulation 7,814

1

vote

1

answer

16

views

maximum error when rounding off multiple times

floating-point truncation-error

answered 37 mins ago Ross Millikan 308k

0

votes

2

answers

14

views

Derivatives: $f_1(x)-f_2(x) = f_1(0)-f_2(0) + \int_0^t [f_1'(u) - f_2'(u)]du$ ??

analysis derivatives

answered 41 mins ago Jaime Grimal Alves 238

15

votes

1

answer

408

views

+400

Graceful graphs with Valence $k$

combinatorics graph-theory recreational-mathematics

modified 41 mins ago Ed Pegg 10.5k

2

votes

0

answers

25

views

proof about irreducible polynomials with complex roots in Q

abstract-algebra polynomials ring-theory roots

asked 42 mins ago angie duque 28

0

votes

1

answer

724

views

Writing Sine and Cosine functions as Fourier Series

fourier-series

modified 43 mins ago Community♦ 1

0

votes

0

answers

7

views

How is a manifestly intrinsic curvature of manifolds defined(without the radius of curvature)?

differential-geometry

asked 44 mins ago Leo Kovacic 11

3

votes

4

answers

24

views

Integrating factor mistakes when solving 1 order ODE

ordinary-differential-equations integrating-factor

answered 47 mins ago MattAllegro 2,640

2

votes

1

answer

31

views

Is this a scalar product of three vectors?

vectors differential-forms

modified 50 mins ago Peter4075 440

3

votes

0

answers

56

views

Shortest path to paint a sphere with a large square or circular brush

calculus geometry optimization spheres solid-geometry

modified 54 mins ago uhoh 698

1

vote

0

answers

9

views

Naturality vs canonicality of double dual

linear-algebra category-theory natural-transformations

modified 57 mins ago A_P 131

1

vote

1

answer

9

views

On curvature for regular curves of arc-length

differential-geometry

answered 59 mins ago Vasily Mitch 3,247

1

vote

0

answers

23

views

Simplest Turing Machine for a particular binary string

recreational-mathematics turing-machines

asked 1 hour ago Ed Pegg 10.5k

0

votes

0

answers

14

views

How to calculate mean and variance in the Weyl group $A_n$?

variance means weyl-group

modified 1 hour ago Jakobian 3,443

0

votes

0

answers

2

views

Real roots of a rescaled confluent hypergeometric function .

roots hypergeometric-function

asked 1 hour ago Przemo 5,114

0

votes

0

answers

11

views

Proving $\|x=y\|\cdot \|\phi(x)\|\le\|\phi(y)\|$ in Boolean valued models

set-theory boolean-algebra forcing

asked 1 hour ago Reveillark 4,890

0

votes

0

answers

4

views

Formation of partial differential equations by eliminating arbitrary constants .

analysis pde

asked 1 hour ago Rabi Kumar Chakraborty 127

0

votes

0

answers

14

views

Homotopy equivalence of S1 and R2-0

general-topology homotopy-theory

asked 1 hour ago jan schütte-engel 11

0

votes

0

answers

20

views

Probability of a car accident occurrence

probability

modified 1 hour ago nmasanta 2,763

-1

votes

2

answers

13

views

Linear Programing: Set binary variable 1, if two variables are not equal

optimization linear-transformations convex-optimization linear-programming

modified 1 hour ago Rob Pratt 641

0

votes

1

answer

13

views

Constrained Reviewer Pairing

optimization linear-programming

answered 1 hour ago saulspatz 21.4k

2

votes

0

answers

10

views

Survival time asymptotics with dependent P(success)

probability probability-theory statistics asymptotics law-of-large-numbers

modified 1 hour ago John 11

1

vote

1

answer

21

views

Bond-price dynamics in the Vasicek model

stochastic-processes stochastic-calculus stochastic-integrals stochastic-pde

answered 1 hour ago Zbigniew 315

0

votes

2

answers

18

views

formula to plot ( 1/4 eliptical) curve with only minx,miny and maxx,maxy

graphing-functions conic-sections

modified 1 hour ago K B Dave 4,086

0

votes

0

answers

14

views

Does there exist a symbol for approximately directly proportional?

relations approximation

asked 1 hour ago Bilal Mirza 1

0

votes

1

answer

29

views

In how many ways can $5$ men and $5$ women be arranged, if two particular women must not be next to a particular man?

combinatorics permutations proof-explanation

modified 1 hour ago N. F. Taussig 47.4k

2

votes

1

answer

27

views

Interpretation Reflection principle

probability brownian-motion markov-process reflection geometric-interpretation

answered 1 hour ago saz 86.4k

1

vote

1

answer

26

views

Determine whether the indicated subset is a subspace of the given vector space

linear-algebra

modified 1 hour ago Berci 64k

0

votes

1

answer

16

views

Sum of monthly contributions with contribution growth and interest

summation finance

modified 1 hour ago saulspatz 21.4k

0

votes

0

answers

17

views

Bounded magnitude of prime divisors

number-theory prime-numbers

asked 1 hour ago Haran 1,594

0

votes

0

answers

15

views

Change of basis associated to several successive rotations

rotations change-of-basis

modified 1 hour ago Anthony 1

0

votes

0

answers

4

views

Cluster assignment matrix transformation

matrices transformation

asked 1 hour ago Mohsen 48

2

votes

0

answers

13

views

Time and space discretization of one dimensional advection equation

numerical-methods taylor-expansion finite-differences

modified 1 hour ago cmk 4,322

8

votes

1

answer

55

views

countable family of open sets

general-topology

modified 1 hour ago Hagen von Eitzen 293k

0

votes

0

answers

20

views

Recurrence relation of population growth

recurrence-relations

modified 1 hour ago user9132502 3

0

votes

1

answer

17

views

What is the PDF for X - C(X - K)Y where C, K are constants and X and Y are independent normal r.vs where the mean and variance are different?

probability probability-theory

answered 1 hour ago Vamshi Kumar Kurva 41

0

votes

0

answers

7

views

Property of Set Function related to Supermodularity

combinatorics elementary-set-theory

asked 1 hour ago raid_the_inarticulate 1

2

votes

4

answers

21

views

Probability of hitting the target for the nth time on the mth throw

probability conditional-probability binomial-distribution

answered 1 hour ago nmasanta 2,763

5

votes

2

answers

127

views

+50

On dual cones: $(K\cap L)^+\subseteq K^+ + L^+$

linear-algebra abstract-algebra geometry optimization convex-analysis

modified 1 hour ago FXV 572

4

votes

1

answer

41

views

Proving using Rolle's Theorem

calculus

answered 1 hour ago LutzL 65.6k

1

vote

1

answer

13

views

Problem with graphing equation in polar form vs Cartesian form

calculus functions graphing-functions polar-coordinates

answered 2 hours ago Mohammad Riazi-Kermani 48.1k

2

votes

0

answers

8

views

Structures preserved by the (co)unit of an adjunction

category-theory

asked 2 hours ago desiigner 241

0

votes

0

answers

8

views

OGF of $\{H_k/k\}$ where $k\ge 1$

generating-functions harmonic-numbers

modified 2 hours ago metamorphy 6,717

0

votes

0

answers

27

views

How many ways can 5 people sit at a round table such that none of them are sitting to the left of the first person they sat behind?

combinatorics

modified 2 hours ago jd94 381

1

vote

1

answer

17

views

Formula for Stereographic Projection of Sphere and its Inverse

stereographic-projections

answered 2 hours ago Ondrej Skopek 126

0

votes

0

answers

14

views

Topological Euler characteristic of a cycle of algebraic curves

algebraic-geometry algebraic-curves

asked 2 hours ago H. Jackson 319

0

votes

0

answers

14

views

flat family of general points in $\mathbb{P}^{3}$

algebraic-geometry

asked 2 hours ago HARRY 114

3

votes

1

answer

23

views

convergence of two mixed iteration formulas: $y_{k+1} = \frac{1}{2} (y_k + z_k^{-1})$ and $z_{k+1} = \frac{1}{2} (z_k + y_k^{-1})$

convergence numerical-methods fixed-point-theorems

answered 2 hours ago Empy2 34.8k

5

votes

3

answers

738

views

Show that if m/n is a good approximation of $\sqrt{2}$ then $(m+2n)/(m+n)$ is better

approximation irrational-numbers rational-numbers

modified 2 hours ago CopyPasteIt 5,044

0

votes

0

answers

28

views

Simple Solve $~[{y = 5 + 2 x + x^a}, {x}]~$ not working?

problem-solving constraints

modified 2 hours ago nmasanta 2,763

0

votes

0

answers

17

views

Using slopes to find orthocentre of a triangle

triangles coordinate-systems slope

asked 2 hours ago Manav Goyal 1

1

vote

0

answers

13

views

Properties of solid ideals of Lie algebras

lie-groups ideals

modified 2 hours ago Morieris 49

1

vote

0

answers

12

views

Showing that the $\sigma$-algebra of countable and cocountable sets on $\mathbb{R}$ is uncountably generated, and also a subset of the Borel algebra

measure-theory

asked 2 hours ago user7924249 30

0

votes

0

answers

6

views

The projection operation ΠF,A(y) for A ∈ Sd + is defined as arg minx∈F kA1/2 (x − y)k for y ∈ R d

optimization machine-learning

asked 2 hours ago Kethan Chauhan 1

0

votes

0

answers

14

views

Differential equation of a RRC circuit as Voltage output/voltage input?

integration ordinary-differential-equations derivatives laplace-transform laplace-method

asked 2 hours ago Ivan 3

6

votes

1

answer

90

views

Numerically robust 2x2 determinant?

numerical-methods numerical-linear-algebra

answered 2 hours ago oskar_matzerath 1

2

votes

0

answers

37

views

Alternative method for computation of Cofactor Matrix?

linear-algebra determinant

modified 2 hours ago jjzun 35

1

vote

0

answers

23

views

Elementary question on Hausdorff distance: Difference between integrals on level sets

real-analysis general-topology functional-analysis hausdorff-distance

modified 2 hours ago Xander Henderson 16k

0

votes

0

answers

2

views

Compute pullback of $(0,1)$-forms with value in $T^{1,0}\textit{SL}_2(\mathbb{C})$ by a left translation.

complex-analysis lie-groups

asked 2 hours ago théo jamin 16

0

votes

0

answers

13

views

Does ATR0 prove existence of uncomputable well-ordering?

logic reference-request computability well-orders reverse-math

asked 2 hours ago user21820 41.8k

0

votes

0

answers

10

views

How to calculate the computational cost of a nonlinear optimization algorithm, which is based on error norm minimization?

computational-complexity computational-mathematics

modified 2 hours ago Adriano 1

3

votes

2

answers

3k

views

How to find the angle between the two tangents on a parabola

calculus analytic-geometry

modified 2 hours ago Rahulbaba 1

2

votes

0

answers

28

views

$f(x+h)=f(x)+\int_0^1(Df(x+r h)h dr)$?

integration convex-optimization approximation intuition

asked 3 hours ago curae 13

0

votes

0

answers

1

view

Find a set of rotations on the Bloch sphere such that they are the most far apart from each other on the 3-sphere, i.e. are the most different

geometry

3 hours ago Haddock 8

0

votes

1

answer

39

views

Mathematical Logic (Shoenfield) : Lemma 1

logic first-order-logic predicate-logic

modified 3 hours ago Mauro ALLEGRANZA 70.3k

2

votes

0

answers

22

views

Solving heat equation for insulated copper rod

pde heat-equation

modified 3 hours ago hkj447 118

0

votes

0

answers

9

views

Need help to compute magnitude spectra(FOURIER series)

fourier-series

asked 3 hours ago DontAskTheEye 92

0

votes

4

answers

66

views

Solve $4x^2-4x-1=0\quad$. I get $\frac{1}{2}$ only, text book also shows $\frac{\sqrt{2}}{2}$

algebra-precalculus

modified 3 hours ago Marvin 438

4

votes

0

answers

45

views

Does there exist some prime $k$ for which there will be exactly two primes of the form $n!+k$?

elementary-number-theory prime-numbers conjectures

modified 3 hours ago Wlod AA 426

5

votes

0

answers

89

views

+50

Maximizing trace of mixed products of two real symmetric matrices

linear-algebra functional-analysis trace symmetric-matrices random-matrices

modified 3 hours ago Jair Taylor 9,183

2

votes

0

answers

34

views

Counting inequivalent binary matrices with special properties

combinatorics matrices

modified 3 hours ago user1551 77.9k

3

votes

1

answer

34

views

Proving that multiplicative groups of two fields F* are isomorphic

abstract-algebra field-theory finite-fields

answered 3 hours ago Maciej Ficek 32

12

votes

3

answers

11k

views

Can someone explain the algorithm for composition of cycles?

algorithms permutations

answered 3 hours ago Jeff Simmons 1

4

votes

0

answers

55

views

Image of quasiprojective variety under closed map

algebraic-geometry

modified 3 hours ago birdiehoweblazer 31

2

votes

1

answer

37

views

Derivative of a taylor polynomial with respect to the center

taylor-expansion

answered 4 hours ago Andreas 9,053

2

votes

0

answers

18

views

Degree of a polynomial over an algebraic curve (in particular Edwards curve)

number-theory algebraic-geometry arithmetic-geometry

asked 4 hours ago AVP82000 11

3

votes

0

answers

27

views

Surface Area of $n$-Dimensional Sphere with Multiple Cuts

geometry multivariable-calculus differential-geometry vector-analysis spheres

modified 4 hours ago Romain S 1,315

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