User Martin Ueding

120

254

votes

9

answers

479k

views

Is a matrix multiplied with its transpose something special?

matrices

Dec 4 at 11:36 Han de Bruijn 15k

3

13

votes

5

answers

2k

views

$n! \leq \left( \frac{n+1}{2} \right)^n$ via induction

Oct 14 '18 at 23:13 Zedelghem 11

1

13

votes

5

answers

323

views

Issues with text problems

problem-solving education

May 12 '12 at 8:33 Ronald 1,323

2

7

votes

1

answer

2k

views

Is the Taylor series comparable to Fourier series and spherical harmonics?

fourier-series taylor-expansion

Jan 5 '13 at 12:47 Martin Ueding 3,791

2

6

votes

2

answers

287

views

Greatest common denominator of measurements

statistics

Jul 24 '13 at 20:58 Community♦ 1

3

6

votes

2

answers

3k

views

When do I write $\sin(x)$ and when $\sin x$?

notation

Oct 13 '12 at 17:36 pritam 9,687

1

5

votes

2

answers

235

views

Is $\dot u/\dot \phi$ is the same as $\mathrm du / \mathrm d\phi$?

derivatives

Jul 18 '14 at 22:53 Community♦ 1

1

4

votes

1

answer

4k

views

Is the trace of a unitary matrix always real?

group-theory trace

Sep 28 '16 at 13:15 Ben Grossmann 185k

1

4

votes

3

answers

490

views

Difference between $\mathop{\text{div}} \vec x$ and $\vec \nabla \cdot \vec x$?

notation

Jan 27 '13 at 14:13 Neal 29k

1

3

votes

1

answer

215

views

Integral using residue theorem

residue-calculus

Jan 6 '14 at 17:14 Ron Gordon 131k

3

votes

3

answers

134

views

Is $f = x^2$ or only $f(x) = x^2$ correct?

notation

Jan 15 '13 at 10:17 Džuris 2,412

3

votes

1

answer

297

views

Heat equation with initial value

partial-differential-equations

Nov 10 '12 at 17:42 Mercy King 14.8k

1

3

votes

1

answer

1k

views

analytic solution to non-linear system of equations.

algebra-precalculus

Jul 4 '12 at 1:59 Gerry Myerson 163k

2

votes

3

answers

198

views

Proof of inequality $\prod_{k=1}^n(1+a_k) \geq 1 + \sum_{k=1}^n a_k$ with induction

inequality induction

Dec 16 at 10:11 Erik Satie 3,160

2

votes

2

answers

99

views

Show that triple product is invariant under rotations

linear-algebra vectors volume rotations orthogonal-matrices

Sep 3 at 20:17 Marvin 31

2

votes

1

answer

67

views

What is the name of this matrix decomposition?

matrix-decomposition

Jul 31 '17 at 14:18 Hellen 532

2

votes

0

answers

74

views

Visually apealing holologous transformation of a given contour

general-topology group-theory recreational-mathematics puzzle visualization

Sep 23 '13 at 18:24 Martin Ueding 3,791

1

2

votes

3

answers

182

views

wave equation with initial values and boundary condititon

partial-differential-equations

Nov 7 '12 at 4:32 Pragabhava 4,698

2

votes

2

answers

156

views

derivative at a given point

calculus notation derivatives

Jul 13 '12 at 19:58 Thomas 39.7k

2

votes

1

answer

158

views

Show that $D: C^1([a, b]) \mapsto C^0([a, b]): f \mapsto f'$ is continuous.

metric-spaces

Apr 24 '12 at 19:28 Community♦ 1

2

votes

1

answer

122

views

Every cover covers sets with $\mathrm{diam}(A) < \lambda$ [duplicate]

general-topology metric-spaces

Apr 23 '12 at 19:15 Community♦ 1

2

votes

1

answer

2k

views

solving a system of equation by rotation

linear-algebra numerical-methods numerical-linear-algebra

Feb 25 '12 at 15:41 Community♦ 1

2

votes

2

answers

3k

views

Integrate $\log(x)$ with Riemann sum

real-analysis integration

Jan 15 '12 at 19:51 Martin Ueding 3,791

2

votes

1

answer

3k

views

Multiple plots in ROOT

math-software graphing-functions

Dec 31 '11 at 4:04 t.b. 71.3k

2

votes

3

answers

121

views

Show $xy\neq0$ is the same as $x\neq0 \wedge y \neq0$

field-theory axioms

Oct 21 '11 at 20:07 JavaMan 12.2k

1

vote

0

answers

124

views

Chain rule for tensor of family of tensor fields

differential-geometry derivatives

May 8 '14 at 14:36 Martin Ueding 3,791

1

vote

2

answers

125

views

Closed complex integral that does not vanish

complex-analysis

Feb 3 '14 at 12:57 Christian Blatter 209k

1

vote

2

answers

81

views

Is it legal to write $A_\mu = (a, b, c, d)$?

notation

Nov 14 '13 at 15:46 Abramo 6,479

1

vote

2

answers

53

views

Limiting the scope of an operator

notation

Jun 25 '13 at 17:57 Ognan 51

1

vote

2

answers

65

views

Is it okay to write $n = n(k)$ to say that $n$ is a function of $k$?

notation

Apr 12 '13 at 12:45 Jonathan Rich 590

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43 Questions

Is a matrix multiplied with its transpose something special?

$n! \leq \left( \frac{n+1}{2} \right)^n$ via induction

Issues with text problems

Is the Taylor series comparable to Fourier series and spherical harmonics?

Greatest common denominator of measurements

When do I write $\sin(x)$ and when $\sin x$?

Is $\dot u/\dot \phi$ is the same as $\mathrm du / \mathrm d\phi$?

Is the trace of a unitary matrix always real?

Difference between $\mathop{\text{div}} \vec x$ and $\vec \nabla \cdot \vec x$?

Integral using residue theorem

Is $f = x^2$ or only $f(x) = x^2$ correct?

Heat equation with initial value

analytic solution to non-linear system of equations.

Proof of inequality $\prod_{k=1}^n(1+a_k) \geq 1 + \sum_{k=1}^n a_k$ with induction

Show that triple product is invariant under rotations

What is the name of this matrix decomposition?

Visually apealing holologous transformation of a given contour

wave equation with initial values and boundary condititon

derivative at a given point

Show that $D: C^1([a, b]) \mapsto C^0([a, b]): f \mapsto f'$ is continuous.

Every cover covers sets with $\mathrm{diam}(A) < \lambda$ [duplicate]

solving a system of equation by rotation

Integrate $\log(x)$ with Riemann sum

Multiple plots in ROOT

Show $xy\neq0$ is the same as $x\neq0 \wedge y \neq0$

Chain rule for tensor of family of tensor fields

Closed complex integral that does not vanish

Is it legal to write $A_\mu = (a, b, c, d)$?

Limiting the scope of an operator

Is it okay to write $n = n(k)$ to say that $n$ is a function of $k$?