User Luke Collins

12

votes

2

answers

885

views

Notation: Is $(\Delta x)^2 = \Delta x^2$?

notation

Jan 10 '16 at 19:57 Mankind 10.8k

2

7

votes

4

answers

427

views

Coefficients of the characteristic polynomial

Jun 25 at 22:09 J.G 2,463

2

7

votes

4

answers

218

views

Defining the Cosine Function from First Principles, intuitively

real-analysis geometry trigonometry

Jan 8 at 3:56 David K 59k

1

7

votes

2

answers

3k

views

What is a homogeneous Differential Equation?

ordinary-differential-equations

Jan 28 '18 at 6:42 Geremia 1,358

2

6

votes

5

answers

547

views

Better proof for $\frac{1+\cos x + \sin x}{1 - \cos x + \sin x} \equiv \frac{1+\cos x}{\sin x}$

trigonometry alternative-proof

Dec 28 '15 at 8:28 Blue 52.5k

3

4

votes

3

answers

107

views

Prove Nice Determinant Equations

linear-algebra matrices determinant

Dec 30 at 10:38 Daniele Tampieri 3,152

2

4

votes

1

answer

977

views

Classify all groups of order 75

group-theory sylow-theory

Jan 28 '18 at 20:30 Dietrich Burde 86.6k

4

votes

2

answers

121

views

Pattern in Isomorphisms between $\mathbb Z_m \times \mathbb Z_n$ and $\mathbb Z_{mn}$

group-theory prime-numbers direct-product

Nov 27 '17 at 23:52 lhf 173k

4

votes

2

answers

324

views

I know that any two left/right cosets are either equal or disjoint, but what about the sets of cosets?

group-theory

Nov 25 '17 at 16:20 G Tony Jacobs 26.4k

1

4

votes

2

answers

471

views

In a ring, are cosets always additive?

abstract-algebra ring-theory

May 31 '17 at 23:35 Trevor Gunn 15.3k

1

4

votes

1

answer

863

views

Why does this prove that a curve is a straight line?

geometry differential-geometry proof-verification curvature

Jan 23 '17 at 16:28 Ted Shifrin 68.7k

3

votes

0

answers

55

views

Recursion-like sequences which are hard to relate recursively

discrete-mathematics induction recurrence-relations

May 11 at 13:06 Luke Collins 2,033

3

votes

1

answer

41

views

A Convention of Set Builder Notation

elementary-set-theory

Jan 13 '18 at 13:27 Asaf Karagila♦ 316k

3

votes

1

answer

57

views

Notation: Relabelling elements of a (finite) set

combinatorics notation

Nov 13 '17 at 8:02 Eike Schulte 789

3

votes

1

answer

70

views

Number of ways of Sitting at Two tables

probability combinatorics combinations

Apr 13 '17 at 14:21 drhab 112k

3

votes

1

answer

320

views

How is this Taylor's Theorem?

calculus analysis taylor-expansion

Mar 9 '17 at 0:37 quantumkid 216

3

votes

1

answer

442

views

Proving that a limit of a piecewise constant function does not exist using $\epsilon$-$\delta$

real-analysis limits epsilon-delta

Dec 6 '16 at 22:58 ervx 10.5k

1

2

votes

1

answer

699

views

What is an exact differential equation?

ordinary-differential-equations

Aug 12 at 11:02 Community♦ 1

2

votes

1

answer

42

views

Hall's theorem and double counting

combinatorics graph-theory

Jun 18 at 14:31 Sandeep Silwal 6,178

1

2

votes

2

answers

52

views

Proof of Gram-Schmidt for countable sets

linear-algebra functional-analysis

Jun 13 at 23:39 jgon 19.2k

2

votes

2

answers

62

views

Is there a difference between $O(x^n)$ and $O((x-1)^n)$?

real-analysis asymptotics taylor-expansion

Dec 24 at 13:04 Matt Samuel 41.2k

1

2

votes

0

answers

44

views

Easiest way to express reversed identity matrix?

linear-algebra matrices graph-theory

Dec 11 at 23:52 Luke Collins 2,033

1

2

votes

2

answers

128

views

Is the function $f(z) = \mathfrak{Re}(z) \mathfrak{Im}(z)$ differentiable at $z=0$?

complex-analysis limits

Jan 10 '18 at 23:14 zhw. 77.9k

1

2

votes

1

answer

45

views

$G$ is a non-cyclic group of order $p^2$. Then $\langle g \rangle \cap \langle k \rangle = \{e\}$

group-theory p-groups

Dec 24 '17 at 13:25 Kenny Lau 20.3k

2

votes

2

answers

342

views

Are there any applications of Algebraic Graph Theory to Computer Science?

linear-algebra graph-theory soft-question computer-science algebraic-graph-theory

Dec 17 '17 at 21:39 ml0105 11.6k

1

2

votes

2

answers

57

views

Limit Involving Generalised Harmonic Numbers

real-analysis limits limits-without-lhopital harmonic-numbers

Dec 15 '17 at 6:47 Claude Leibovici 133k

2

votes

2

answers

91

views

Transforming a function $f: \mathbb N^2 \to A$ to a function $f:\mathbb N\to A$ in a zig-zag manner

analysis functions

Nov 30 '17 at 4:21 Duchamp Gérard H. E. 2,706

1

2

votes

2

answers

77

views

Express the set $\{3, \{3\}, \{\{3\}\}, \{\{\{3\}\}\}, \dots \}$ in set-builder notation.

elementary-set-theory

Nov 18 '17 at 18:13 Malice Vidrine 6,595

2

votes

1

answer

113

views

Proof that an abelian group whose action has one orbit has a singleton stabiliser.

group-theory permutations

Nov 15 '17 at 19:49 James 7,242

2

votes

1

answer

259

views

Determinant of a symmetric zero-diagonal matrix

linear-algebra algorithms eigenvalues-eigenvectors

Sep 20 '17 at 5:59 Misha Lavrov 53.3k

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74 Questions

Notation: Is $(\Delta x)^2 = \Delta x^2$?

Coefficients of the characteristic polynomial

Defining the Cosine Function from First Principles, intuitively

What is a homogeneous Differential Equation?

Better proof for $\frac{1+\cos x + \sin x}{1 - \cos x + \sin x} \equiv \frac{1+\cos x}{\sin x}$

Prove Nice Determinant Equations

Classify all groups of order 75

Pattern in Isomorphisms between $\mathbb Z_m \times \mathbb Z_n$ and $\mathbb Z_{mn}$

I know that any two left/right cosets are either equal or disjoint, but what about the sets of cosets?

In a ring, are cosets always additive?

Why does this prove that a curve is a straight line?

Recursion-like sequences which are hard to relate recursively

A Convention of Set Builder Notation

Notation: Relabelling elements of a (finite) set

Number of ways of Sitting at Two tables

How is this Taylor's Theorem?

Proving that a limit of a piecewise constant function does not exist using $\epsilon$-$\delta$

What is an exact differential equation?

Hall's theorem and double counting

Proof of Gram-Schmidt for countable sets

Is there a difference between $O(x^n)$ and $O((x-1)^n)$?

Easiest way to express reversed identity matrix?

Is the function $f(z) = \mathfrak{Re}(z) \mathfrak{Im}(z)$ differentiable at $z=0$?

$G$ is a non-cyclic group of order $p^2$. Then $\langle g \rangle \cap \langle k \rangle = \{e\}$

Are there any applications of Algebraic Graph Theory to Computer Science?

Limit Involving Generalised Harmonic Numbers

Transforming a function $f: \mathbb N^2 \to A$ to a function $f:\mathbb N\to A$ in a zig-zag manner

Express the set $\{3, \{3\}, \{\{3\}\}, \{\{\{3\}\}\}, \dots \}$ in set-builder notation.

Proof that an abelian group whose action has one orbit has a singleton stabiliser.

Determinant of a symmetric zero-diagonal matrix