Mathematics Stack Exchange

0

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0

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2

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Area under paraboloid $z=x^{2}+y^{2}$ with $z \geq 1$

integration differential-geometry differential

asked 2 mins ago Madhu 729

-1

votes

2

answers

21

views

how to solve modular quadratic equation?

algebra-precalculus

answered 4 mins ago 1123581321 342

0

votes

0

answers

2

views

About conservative extensions of first order theories?

first-order-logic

modified 5 mins ago Zuhair 350

2

votes

2

answers

42

views

If $A^kB^l=B^lA^k$ for all $k,l>1$, is $AB=BA$?

linear-algebra matrices eigenvalues-eigenvectors

answered 5 mins ago user1551 73.9k

0

votes

0

answers

6

views

Additivity of a limiting distribution

probability-theory measure-theory probability-distributions

modified 6 mins ago fesman 181

0

votes

0

answers

3

views

Components of a Continuous Random Variable

probability-theory random-variables

asked 6 mins ago The Substitute 1,898

0

votes

1

answer

9

views

Convolution of Delta Functions with a pole

integration fourier-analysis fourier-series fourier-transform convolution

modified 6 mins ago reuns 21.8k

0

votes

0

answers

7

views

The set of all sums of characteristic functions of integer ideals up to $\sqrt{|n|}$ forms a ring?

abstract-algebra elementary-number-theory prime-numbers ideals integers

modified 6 mins ago BananaCats 9,323

1

vote

1

answer

18

views

Proving that there are infinitely many irreducible polynomial in $\mathbb{Z}_{5} [x]$

abstract-algebra polynomials irreducible-polynomials

modified 6 mins ago dcolazin 369

0

votes

2

answers

12

views

Value of [a b c] from (a×(b×c)).(a×c)?

vectors cross-product

answered 8 mins ago Lord Shark the Unknown 107k

0

votes

0

answers

3

views

The truel problem, why aren't the better players intentionally missing?

probability game-theory

asked 8 mins ago Vũ Lê Thế Anh 1

0

votes

1

answer

7

views

Prove that $\sum^n_{i=1} X_i$ and $\prod^n_{i=1} X_i$ are sufficient statistics for the gamma distribution

statistics functions gamma-distribution data-sufficiency

answered 8 mins ago franzk 145

0

votes

1

answer

42

views

What is the probability that I will be alive a month from now?

probability

modified 8 mins ago Commodore 11

0

votes

0

answers

6

views

Cancelling differential terms

calculus algebra-precalculus differential-algebra

asked 11 mins ago Saumil Sood 9

0

votes

0

answers

12

views

If $Y_n=E(X|\mathcal{F}_n)$ for some $\mathcal{F}_n \subset \mathcal{F}$ and if $Y_n \to Y$ with probability one. Show $Y_n \to Y$ in $L^1$.

probability-theory convergence conditional-expectation

modified 11 mins ago saz 81.9k

0

votes

1

answer

15

views

$y_{n+1} = y_n - \frac{y_n^2}{3}$ general formula

sequences-and-series induction

answered 13 mins ago 1123581321 342

0

votes

0

answers

4

views

Question about Helmholtz's paper “ON THE CONSERVATION OF FORCE”

ordinary-differential-equations analytic-geometry coordinate-systems

asked 13 mins ago Vaggelis Kyrilas 40

0

votes

0

answers

5

views

$\int_{\mathbb R^d} (1+ |x-n|^2)^{s} |f(x)|^2 dx = \sum_{k\in \mathbb Z^d}(1+ |k-n|^2)^s \int_{I_k}|f(x)|^2 dx?$

real-analysis integration lp-spaces

asked 14 mins ago Math Learner 327

0

votes

1

answer

11

views

How to guess a solution of an ODE when the LHS includes cosine?

ordinary-differential-equations

modified 14 mins ago Rodrigo de Azevedo 13.2k

1

vote

0

answers

7

views

Find minimum perimeter of the triangle circumscribing semicircle

algebra-precalculus geometry circles maxima-minima

asked 15 mins ago Umesh shankar 3,089

0

votes

0

answers

4

views

Prove reagarding Recurrence Relations

discrete-mathematics recurrence-relations recursion

asked 18 mins ago kratoooos 3

0

votes

1

answer

23

views

Given a continuous charge distribution of a sphere calculate the electric field away:

integration definite-integrals physics

modified 20 mins ago user 6,045

0

votes

0

answers

5

views

Find a Function with compact support

real-analysis measure-theory continuity compactness

asked 21 mins ago S_Alex 192

0

votes

1

answer

26

views

expectation of the sign of product of bivariate normal variables

statistics probability-distributions brownian-motion

answered 22 mins ago Lnct3 191

0

votes

0

answers

9

views

Diagonal elements and Eigenvalues of a matrix

matrices eigenvalues-eigenvectors matrix-equations block-matrices

asked 25 mins ago Abhiram V P 16

5

votes

1

answer

47

views

Path-continuity and the Axiom of Choice

general-topology multivariable-calculus continuity axiom-of-choice path-connected

modified 30 mins ago Eric Wofsey 191k

0

votes

0

answers

7

views

Integration of function having Logarithmic,exponential terms

definite-integrals

asked 30 mins ago jacky 1,346

0

votes

0

answers

13

views

operator core of a fourier multiplier

functional-analysis fourier-analysis unbounded-operators

modified 32 mins ago Ribhu 238

0

votes

0

answers

2

views

Measurable function f is summable iff |f| is summable

integration measure-theory

asked 34 mins ago franzk 145

2

votes

1

answer

28

views

Understanding the Poincare-Bendixson theorem.

real-analysis

modified 35 mins ago gigaster 141

2

votes

1

answer

27

views

Algebraic Geometry: Let $\varphi: k[X,Y] \rightarrow k(t)$ defined by $\varphi (f(X,Y)) = f(\frac{1-t^2}{t^2+1},\frac{2t}{t^2+1})$ .

abstract-algebra algebraic-geometry ideals

answered 39 mins ago Alex Wertheim 16.2k

0

votes

0

answers

6

views

A system of bivariate cubics

algebra-precalculus systems-of-equations cubic-equations

asked 40 mins ago Awe Kumar Jha 572

0

votes

1

answer

9

views

Let X be sequentially compact. Then X is also countably compact.

compactness

answered 44 mins ago Kavi Rama Murthy 70.8k

0

votes

0

answers

9

views

Finding similarity dissimilarity between different groups of vectors

linear-algebra machine-learning

modified 45 mins ago Jay Qadan 1

2

votes

1

answer

50

views

Solving the improper integral

integration complex-numbers improper-integrals residue-calculus

answered 49 mins ago Claude Leibovici 125k

1

vote

0

answers

5

views

Gershgorin circle theorem in block matrix

matrices inequality matrix-equations block-matrices gershgorin-sets

asked 51 mins ago Abhiram V P 16

0

votes

2

answers

12

views

About singularity

complex-analysis

answered 52 mins ago Kavi Rama Murthy 70.8k

1

vote

1

answer

20

views

Finding the sum of the reciprocals of the positive divisors of a number

elementary-number-theory prime-numbers prime-factorization divisor-sum

answered 52 mins ago астон вілла олоф мэллбэрг 40.1k

0

votes

1

answer

27

views

Proof that eigenvalues of matrix with zero trace are all equal to zero

linear-algebra eigenvalues-eigenvectors trace

modified 54 mins ago Chinnapparaj R 5,820

3

votes

3

answers

96

views

Isn't there any divisor $k$ of $n^4$ such that $n^2-n<k<n^2$?

elementary-number-theory divisibility

modified 55 mins ago robjohn♦ 270k

0

votes

0

answers

8

views

Linear extension of a vector field

nonlinear-analysis

asked 56 mins ago Mirko Aveta 103

1

vote

1

answer

16

views

A 5 member committee is to be chosen from 15 students and 10 teachers

probability

modified 59 mins ago user1952500 789

2

votes

1

answer

35

views

Solution to this second order linear differential equation with variable coefficients

ordinary-differential-equations pde laplace-transform

answered 59 mins ago doraemonpaul 12.8k

0

votes

0

answers

5

views

Constrained Optimization for Location Allocation problem- new supply center selection for maximal coverage of demand points

optimization linear-programming nonlinear-optimization

asked 1 hour ago Varun Srivastava 1

0

votes

0

answers

6

views

Minimum distance between two subsets of two closed linear subspaces $M,N$ of a Hilbert space $H$ ($H = M \oplus N$)

functional-analysis hilbert-spaces projection

asked 1 hour ago U2647 84

0

votes

1

answer

38

views

Why is $E_A(Pr(\Theta \leq 0 | A= \alpha, X=x) | X=x)) = Pr_{\pi}(\Theta \leq 0 | X = x)$?

probability conditional-expectation conditional-probability expected-value

answered 1 hour ago masoud 103

0

votes

0

answers

15

views

Testing hypothesis using the Neyman-Pearson Lemma

statistics hypothesis-testing parameter-estimation

modified 1 hour ago StubbornAtom 6,308

1

vote

1

answer

32

views

What is the value of this summation

sequences-and-series

modified 1 hour ago Tianlalu 3,182

0

votes

1

answer

17

views

Does 𝑓({∅}) = {∅}?

functions discrete-mathematics elementary-set-theory

answered 1 hour ago Le Anh Dung 1,464

0

votes

0

answers

20

views

Order of accuracy of Numerov's method

ordinary-differential-equations numerical-methods

modified 1 hour ago Rodrigo de Azevedo 13.2k

0

votes

0

answers

14

views

100 people (or some multiple of 100) want to travel from San Diego to LA

linear-algebra optimization recreational-mathematics

asked 1 hour ago Virad Gupta 37

0

votes

0

answers

6

views

Projection of $\mathbb{R}^2$ onto the line $y=x$, but NOT with respect to the usual inner product.

linear-algebra inner-product-space

asked 1 hour ago user636164 26

2

votes

1

answer

23

views

Prove a function with disjoint open intervals is continuous

real-analysis

modified 1 hour ago Martin R 30.5k

0

votes

1

answer

14

views

Direction Ratio of line when one of contributing plane is constant

geometry 3d plane-geometry

modified 1 hour ago amitava 221

0

votes

0

answers

20

views

If $A+B$ is a compact non-zero operator, which properties follow for $A$ and $B$?

functional-analysis banach-spaces compact-operators

modified 1 hour ago TG2 590

4

votes

0

answers

15

views

$M_n(R)/[M_n(R), M_n(R)] \cong R/[R,R]$

linear-algebra abstract-algebra lie-algebras

modified 1 hour ago Omnomnomnom 129k

2

votes

0

answers

9

views

Which polynomial forms generate non-trivial semigroups of integers under multiplication?

number-theory integers

asked 1 hour ago frogeyedpeas 7,643

0

votes

1

answer

9

views

Intuitive understanding of Gradient-based Optimization

gradient-descent

answered 1 hour ago parsiad 18.6k

0

votes

0

answers

12

views

there exists a $u \in L^\infty(X)$ such that $\lim_{x \to \infty} \int_{X} u_nv = \int_{X} uv \space\space \forall v \in L^1(X)$

real-analysis

asked 1 hour ago Doug Adam 3

0

votes

0

answers

15

views

TI-nspire CX CAS giving weird/incorrect indefinite integral

integration calculator

modified 2 hours ago Dreadpirate Snuffles 1

1

vote

1

answer

32

views

Prove independence of two random variables.

probability random-variables independence

modified 2 hours ago masoud 103

1

vote

1

answer

35

views

Prove by induction that $x^{n}$ is continuous

real-analysis

modified 2 hours ago rolandcyp 1,775

0

votes

3

answers

32

views

Prove that $\frac{2-2a^2}{1+a^2}+\frac{1-b^2}{1+b^2}+\frac{1-c^2}{1+c^2} \leq \frac{9}{4}$

inequality substitution a.m.-g.m.-inequality cauchy-schwarz-inequality

modified 2 hours ago Michael Rozenberg 109k

2

votes

0

answers

18

views

Fundamental theorem of Algebra to prove countable set

real-analysis proof-verification

asked 2 hours ago MAC 38

0

votes

0

answers

13

views

Mean Value Inequality in Banach Space without Hahn-Banach or Integrals

real-analysis functional-analysis banach-spaces normed-spaces frechet-derivative

modified 2 hours ago Matematleta 11.8k

1

vote

1

answer

40

views

How to find an exact solution to a certain linear second-order non-homogeneous differential equation

ordinary-differential-equations

modified 2 hours ago doraemonpaul 12.8k

0

votes

0

answers

10

views

if $a\in acl(b)$, then there's $\varphi(x;b)\in t_p(a;b)$ algebraic and $\varphi(x;c)$ algebraic for all $c$

model-theory

asked 2 hours ago fbg 461

2

votes

1

answer

28

views

$\mathbb R$-points of semisimple real algebraic groups, connectivity, and Cartan involutions: some questions

algebraic-geometry representation-theory lie-groups lie-algebras algebraic-groups

answered 2 hours ago Stefan Dawydiak 324

1

vote

0

answers

13

views

A question about a lemma in Kenneth Kunen's article “Some points in $\beta \mathbb{N}$.”

measure-theory set-theory proof-explanation boolean-algebra

modified 2 hours ago Dbchatto67 2,323

0

votes

0

answers

27

views

Question on differential linear operator

linear-algebra vector-spaces linear-transformations

modified 2 hours ago Akash Patalwanshi 1,017

0

votes

0

answers

13

views

sequence of functions converges to the square wave

real-analysis complex-analysis metric-spaces fourier-analysis periodic-functions

asked 2 hours ago qinr 42

1

vote

1

answer

18

views

Understanding interpretation of a predicate

logic first-order-logic predicate-logic quantifiers

answered 2 hours ago Graham Kemp 87.5k

0

votes

1

answer

8

views

does this formula about hyper-pyramids work? and if so why

general-topology reference-request

answered 2 hours ago Ross Millikan 300k

1

vote

1

answer

16

views

Application of Lévy Zero-One Law

probability probability-theory convergence conditional-expectation martingales

answered 3 hours ago Mike Earnest 26.1k

0

votes

0

answers

4

views

Hoare triple: Loop invariant and correctness

discrete-mathematics logic predicate-logic

asked 3 hours ago BoiD 11

7

votes

1

answer

812

views

Klein bottle homeomorphic to union of Möbius strip

general-topology klein-bottle mobius-band

modified 3 hours ago Community♦ 1

0

votes

1

answer

6

views

Is marginalization a sum of conditioned observations?

probability conditional-probability marginal-distribution

answered 3 hours ago Graham Kemp 87.5k

4

votes

1

answer

30

views

The map of graded rings $k[w, x, y, z] \rightarrow k[s, t]$ induces a closed embedding $\mathbb{P}_k^1 \rightarrow \mathbb{P}_k^3$

algebraic-geometry commutative-algebra projective-geometry projective-space projective-schemes

answered 3 hours ago Alex Wertheim 16.2k

2

votes

1

answer

30

views

Find $\lim_{n \rightarrow\infty } P_n$whreas $P_n=\frac{2^3-1}{2^3+1}\cdot\frac{3^3-1}{3^3+1}\cdot\cdot\cdot\frac{n^3-1}{n^3+1}$.

real-analysis limits

answered 3 hours ago Lord Shark the Unknown 107k

0

votes

0

answers

8

views

Help finding 16 more critical points of a vector valued function from $\mathbb{R}^3 \supseteq G \rightarrow \mathbb{R}?$

real-analysis multivariable-calculus linear-transformations partial-derivative vector-analysis

modified 3 hours ago Manaman1000 1

1

vote

1

answer

28

views

Showing why $\Bbb Z^-∩\Bbb Z^+=∅$ is true

set-theory

modified 3 hours ago Eevee Trainer 8,843

0

votes

0

answers

13

views

Proof of Cramér-Lundberg inequality

real-analysis probability-theory stochastic-processes martingales stopping-times

asked 3 hours ago D Ford 677

0

votes

0

answers

17

views

Simplifying a rational expression with two variables

algebra-precalculus

asked 3 hours ago mtillum 1

0

votes

0

answers

7

views

Effectiveness of Landau's Prime Ideal Theorem

analytic-number-theory

asked 3 hours ago Nell 103

0

votes

0

answers

8

views

show that $f$ is Ergodic with respect of Lebesgue measure.

ergodic-theory

asked 3 hours ago Ricardo Freire 562

0

votes

0

answers

14

views

how to decompose matrix like this?

matrices matrix-decomposition

modified 3 hours ago deltaskelta 112

1

vote

0

answers

10

views

Can one prescribe the hessian?

linear-algebra riemannian-geometry hessian-matrix

asked 3 hours ago L.F. Cavenaghi 2,326

2

votes

0

answers

15

views

Example of not smooth morphisim

algebraic-geometry

asked 3 hours ago Yuyi Zhang 161

1

vote

0

answers

15

views

How to prove that this two maps on torus are not homotopic?

differential-topology smooth-manifolds

asked 3 hours ago ZoLo Kur 6

2

votes

1

answer

13

views

Largest eigenvalue of the Laplacian Matrix in an odd cycle

linear-algebra graph-theory eigenvalues-eigenvectors characteristic-functions graph-laplacian

answered 4 hours ago M. Vinay 7,193

0

votes

2

answers

60

views

Prove that $ \int _{0}^{\infty}\frac{\sin x}{x}dx=\frac{\pi}{2}$

fourier-analysis

answered 4 hours ago DisintegratingByParts 60.1k

0

votes

0

answers

9

views

Signed Measure equivalent definition

analysis measure-theory signed-measures

modified 5 hours ago J. W. Tanner 4,017

3

votes

0

answers

14

views

Equations of 1st order but not of 1st degree.

ordinary-differential-equations

asked 5 hours ago Lucifer 45

0

votes

2

answers

28

views

If A, B, and C are Boolean variables, which of the following statements are true?

discrete-mathematics boolean-algebra

modified 5 hours ago Gray 18

0

votes

2

answers

16

views

Geometric argument for integral test. Confused about integral endpoints.

sequences-and-series

answered 5 hours ago marty cohen 74.9k

1

vote

0

answers

18

views

Given 2 complete vector fields $X, Y$, and the fact that $[X, Y] = 0$, what is the resulting flow of the vector field $X+Y$?

differential-geometry

modified 5 hours ago Brian 1,200

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