Hottest Questions This Month

89

votes

20

answers

20k

views

How do you explain to a 5th grader why division by zero is meaningless?

divisibility education

modified 57 mins ago greedoid 26.6k

84

votes

11

answers

12k

views

Is there any conjecture that has been proved to be solvable/provable but whose direct solution/proof is not yet known?

answered 2 days ago Gerry Myerson 143k

35

votes

6

answers

4k

views

Drinking habits riddle: the village is $90$%$+80$%$+70$%$+60$%$ = 300$ % saturated with liquids

combinatorics algebra-precalculus puzzle

modified Aug 12 at 19:13 Shashi 6,146

38

votes

9

answers

4k

views

Should a mathematical proof be 'convincing'?

proof-writing philosophy formal-proofs

answered yesterday Harshkirat Singh 1

59

votes

3

answers

6k

views

Optimal strategy for cutting a sausage?

combinatorics logic recreational-mathematics fair-division

modified Aug 15 at 13:39 Mario Carneiro 18.1k

39

votes

3

answers

3k

views

What is the crime of lèse-Bourbaki?

abstract-algebra math-history mathematical-french

modified yesterday Rodrigo de Azevedo 12.6k

23

votes

7

answers

2k

views

What problems have been frequently computationally verified for large values?

reference-request recreational-mathematics math-history big-list

answered Aug 7 at 8:57 corey979 296

21

votes

10

answers

3k

views

What exactly is circular reasoning?

logic philosophy proof-theory

modified Aug 3 at 23:18 Joseph Myers 299

10

votes

10

answers

4k

views

How do we understand 6 people trying something is not 6 times the success rate? [closed]

probability

modified Jul 23 at 23:48 Martin Argerami 116k

15

votes

13

answers

2k

views

Geometry: Prove that two angles are not equal

geometry alternative-proof

answered Jul 23 at 3:16 Paul Ferris 3

14

votes

6

answers

4k

views

Integrating both sides of an equation: what does it really mean?

calculus

modified Aug 7 at 19:22 rcgldr 128

16

votes

5

answers

3k

views

In combinatorics, why is asking the opposite problem often times easier? [closed]

combinatorics

modified Aug 3 at 6:59 Martin Roberts 1,189

11

votes

9

answers

3k

views

Does there exist a right triangle with area 7 and perimeter 12?

algebra-precalculus geometry

answered yesterday Rosie F 1,150

14

votes

3

answers

2k

views

Why can you find the roots a of polynomial by factoring it?

algebra-precalculus functions polynomials roots

modified Aug 14 at 0:28 Daniel Buck 2,354

18

votes

4

answers

1k

views

How to simplify $\int{\sqrt[4]{1-8{{x}^{2}}+8{{x}^{4}}-4x\sqrt{{{x}^{2}}-1}+8{{x}^{3}}\sqrt{{{x}^{2}}-1}}dx}$?

real-analysis integration indefinite-integrals radicals nested-radicals

modified Aug 2 at 12:02 Kitegi 551

12

votes

9

answers

4k

views

Is there a mathematical notation for “repeat $X$ until $Y$”?

algorithms notation

modified Aug 9 at 22:56 zooby 855

31

votes

2

answers

2k

views

How few disks are needed to cover a square efficiently?

geometry discrete-geometry tiling

modified Aug 15 at 8:53 Jaap Scherphuis 3,508

7

votes

6

answers

2k

views

How to get the shaded region of the rectangle?

geometry

modified Jul 24 at 12:43 Community♦ 1

6

votes

5

answers

1k

views

What is $\log(n+1)-\log(n)$?

real-analysis numerical-methods logarithms

modified Jul 23 at 8:23 user21820 35.8k

5

votes

8

answers

2k

views

Second marble is of same color

probability combinatorics

modified Jul 25 at 21:52 tdluong 131

12

votes

6

answers

2k

views

Between any two powers of $5$ there are either two or three powers of $2$

inequality exponentiation

modified Jul 28 at 2:07 Dave 126

15

votes

3

answers

2k

views

What does this notation in this SAT-Test question mean?

notation parametric

modified Aug 4 at 22:29 Jasper 347

10

votes

3

answers

2k

views

Conjugate of real number

radicals real-numbers rational-numbers

modified Jul 30 at 19:59 Community♦ 1

10

votes

4

answers

1k

views

How to determine if a set of five $2\times2$ matrices is independent

linear-algebra matrices

modified Jul 26 at 20:59 robjohn♦ 258k

17

votes

3

answers

1k

views

Where did I go wrong with my odd proof that $\frac{3dx}{3x} = \frac{5dx}{5x} \iff 3=5$?

calculus fake-proofs

modified Aug 12 at 20:40 amWhy 189k

13

votes

3

answers

1k

views

A proof of the product rule using the single variable chain rule?

calculus alternative-proof

answered Aug 2 at 20:06 Tyler6 565

9

votes

8

answers

298

views

Evaluating $\lim_{x\to0} \frac{\cos x - \cos 3x}{\sin 3x^2 - \sin x^2}$

calculus limits trigonometry

modified Jul 31 at 10:39 mathcounterexamples.net 24.6k

11

votes

6

answers

601

views

What is the physical significance of the determinants of orthogonal matrices having the value of $\pm 1$?

linear-algebra matrices determinant orthogonal-matrices

modified Aug 12 at 21:43 Xander Henderson 13.1k

16

votes

5

answers

718

views

Integer solutions to $x^3=y^3+2y+1$?

algebra-precalculus elementary-number-theory contest-math diophantine-equations cubic-equations

modified 2 days ago Daniel Buck 2,354

14

votes

3

answers

2k

views

Polynomial cannot have all roots real?

calculus polynomials roots

modified Aug 16 at 20:08 Rodrigo de Azevedo 12.6k

10

votes

4

answers

2k

views

Is there a formal term for the placement of two symbols next to each other to imply an operation?

notation terminology definition

answered Aug 6 at 16:41 Acccumulation 4,493

11

votes

8

answers

1k

views

Two Dirac delta functions in an integral?

calculus multivariable-calculus mathematical-physics dirac-delta quantum-mechanics

answered Aug 13 at 21:14 Acccumulation 4,493

14

votes

3

answers

2k

views

Why is $\sin : \mathbb{R} \to [-5,5] $ different from $\sin : \mathbb{R} \to \mathbb{R}$? [closed]

functions

answered Aug 3 at 11:08 jimalton 11

13

votes

3

answers

2k

views

An invisible ghost jumping on a regular hexagon

combinatorics combinatorial-game-theory extremal-combinatorics

modified Aug 1 at 22:12 Community♦ 1

11

votes

5

answers

821

views

Why multiplying powers of prime factors of a number yields number of total divisors?

elementary-number-theory prime-numbers divisor-counting-function

modified Aug 14 at 13:02 John 141

7

votes

7

answers

3k

views

Does it follow from Gödel's theorem that this world cannot be fully described by math?

logic soft-question philosophy incompleteness

answered Jul 30 at 20:41 Tanner Swett 3,660

3

votes

5

answers

1k

views

Is there a perfect square that is the sum of $3$ perfect squares?

number-theory square-numbers

modified Jul 27 at 18:07 Will Jagy 97.3k

35

votes

4

answers

4k

views

A conjecture involving prime numbers and circles

number-theory prime-numbers euclidean-geometry circle

modified 1 hour ago Andrea Prunotto 833

8

votes

7

answers

821

views

If the order in a set doesn’t matter, can we change order of, say, $\Bbb{N}$?

elementary-set-theory natural-numbers

modified Aug 15 at 19:52 Allawonder 1,657

8

votes

6

answers

1k

views

What is the definition of “canonical”? [closed]

abstract-algebra category-theory representation-theory

modified Aug 1 at 12:02 user529760 714

15

votes

3

answers

664

views

Smallest cube ending in $2017$

modular-arithmetic

modified Aug 12 at 21:57 Xander Henderson 13.1k

11

votes

4

answers

1k

views

Is there a proof that performing an operation on both sides of an equation preserves equality?

abstract-algebra group-theory proof-writing axioms

answered 2 days ago Doug Spoonwood 7,712

12

votes

1

answer

2k

views

How can $0.999\dots$ not equal $1$?

real-numbers nonstandard-analysis

modified Jul 24 at 20:32 Xander Henderson 13.1k

23

votes

2

answers

602

views

A finite group such that every element is conjugate to its square is trivial

abstract-algebra group-theory finite-groups

modified Aug 16 at 15:14 user1729 16.8k

10

votes

6

answers

405

views

Galois Theory by Rotman, Exercise 60, a field of four elements by using Kroenecker's theorem and adjoining a root of $x^4-x$ to $\Bbb Z_2$

abstract-algebra galois-theory finite-fields extension-field

modified Aug 5 at 23:35 Asaf Karagila♦ 292k

6

votes

6

answers

664

views

Colouring of $\mathbb{N}$ that avoids all non-constant infinite arithmetic progressions?

combinatorics problem-solving integers coloring arithmetic-progressions

modified 4 hours ago user21820 35.8k

8

votes

3

answers

1k

views

A bag contains 3 red, 4 blue, and 5 green balls. [closed]

probability combinatorics

modified Jul 25 at 22:50 InterstellarProbe 2,217

3

votes

4

answers

606

views

Ring whose identity is $42$? [closed]

abstract-algebra ring-theory

modified Aug 1 at 23:42 Asaf Karagila♦ 292k

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