User ecjb

5 votes

1 answer

258 views

Second Lemma of variation Calculus to prove the Euler-Lagrange equation

asked Jan 6, 2019 at 15:43

5 votes

1 answer

2k views

Visual representation of difference between closed, bounded and compact sets

asked May 12, 2019 at 16:06

4 votes

3 answers

6k views

Good set of exercises with solutions for linear algebra

asked Feb 1, 2019 at 21:41

3 votes

1 answer

781 views

Derivative of a multivariate quadratic function

asked Mar 30, 2019 at 9:23

3 votes

2 answers

40 views

$\lim_{n \to \infty}\frac{d(x_{n+1}, x_\star)}{d(x_n, x_\star)} = 0$, show that $d(x_n, x_\star)\leq K\varepsilon^n \quad \text{for all }n\geq 0$

asked Jul 22, 2019 at 9:16

3 votes

1 answer

550 views

Finding the Best linear unbiased estimator of the mean using Lagrange Multiplier

asked Jul 14, 2019 at 15:04

3 votes

4 answers

72 views

If $A \in \mathbb{R}^{n\times n}$ and $\textbf{x}\in \mathbb{R}^{n}$why $A = \frac{1}{2} A + \frac{1}{2} A^\top $ is not always true?

asked Sep 24, 2019 at 16:17

3 votes

3 answers

99 views

Prove that if $\eta = \log(\frac{\phi}{1-\phi})$ then $\phi = \frac{1}{1+e^{-\eta}}$

asked Oct 13, 2019 at 9:11

2 votes

2 answers

78 views

Detail in the proof that eigenvectors are orthogonal

asked Jan 1, 2020 at 9:14

2 votes

3 answers

478 views

Computation of $(\textbf{u}\cdot \nabla)\textbf{u}$ in the Navier stokes equation: inner or outer product?

asked Jan 24, 2020 at 17:17

2 votes

2 answers

68 views

show that $\textbf{u} = \textbf{v}$ if $\langle \textbf{u}, \textbf{h}\rangle + o(\|h\|) = \langle \textbf{v}, \textbf{h}\rangle + o(\|h\|)$

asked Jul 21, 2019 at 10:08

2 votes

1 answer

789 views

Linear algebra: Minimizing a quadratic form under linear constraints

asked Jul 14, 2019 at 20:18

2 votes

1 answer

723 views

Show that A-conjugate directions are are linearly independent.

asked Jul 27, 2019 at 10:58

2 votes

2 answers

57 views

How should I know that $C^3 - 2 C + 1$ factors as $(C-1)\left(\left(C+\frac12\right)^2-\frac54\right)$?

asked Jul 31, 2019 at 13:25

2 votes

3 answers

1k views

Laplace equation: What is the difference between divergence operator and gradient operator both represented by $\nabla$? (in wikipedia article)

asked Jun 21, 2019 at 8:56

2 votes

1 answer

299 views

Taylor approximation of cos function

asked Sep 28, 2018 at 22:09

2 votes

1 answer

424 views

how fit a model with data following asymptotic / sigmoid pattern

asked Jul 17, 2018 at 6:57

2 votes

1 answer

1k views

Calculate the Eigenvalue of a 3x3 matrix

asked Sep 24, 2018 at 21:48

2 votes

1 answer

579 views

LU Decomposition: difference between between hand calculation and solver?

asked Oct 3, 2018 at 19:31

2 votes

1 answer

82 views

Line integral in a vector field

asked Oct 13, 2018 at 16:05

2 votes

1 answer

122 views

vector field out of a sphere

asked Oct 14, 2018 at 9:30

1 vote

0 answers

39 views

what is the significance of $\kappa$ in the proof of inconditional stability of the Crank-Nicolson scheme

asked Dec 2, 2018 at 18:22

1 vote

1 answer

87 views

Exercise using the derivation of the Euler-Lagrange equation

asked Dec 9, 2018 at 10:03

1 vote

1 answer

57 views

Question about line integral

asked Oct 6, 2018 at 13:50

1 vote

1 answer

3k views

Computing the condition number of a matrix

asked Oct 7, 2018 at 12:47

1 vote

3 answers

144 views

Matrices - homogeneous system

asked Apr 4, 2018 at 21:28

1 vote

2 answers

561 views

18.02 MIT Multivariate calculus - Computing most rapid decrease using directional derivative

asked May 14, 2018 at 7:23

1 vote

1 answer

1k views

Finite difference - Explicit / Implicit / Crank Nicolson - Does the implicit method require the least memory?

asked Jan 3, 2019 at 15:28

1 vote

0 answers

292 views

Using Newton Raphson's method to solve a non-linear boundary value problem?

asked Jan 3, 2019 at 19:01

1 vote

1 answer

60 views

Identify $f$, $f'$, $u$ and $u'$ in an equation to use chain rule

asked Sep 29, 2018 at 16:43

Stack Exchange Network

88 Questions

Second Lemma of variation Calculus to prove the Euler-Lagrange equation

Visual representation of difference between closed, bounded and compact sets

Good set of exercises with solutions for linear algebra

Derivative of a multivariate quadratic function

$\lim_{n \to \infty}\frac{d(x_{n+1}, x_\star)}{d(x_n, x_\star)} = 0$, show that $d(x_n, x_\star)\leq K\varepsilon^n \quad \text{for all }n\geq 0$

Finding the Best linear unbiased estimator of the mean using Lagrange Multiplier

If $A \in \mathbb{R}^{n\times n}$ and $\textbf{x}\in \mathbb{R}^{n}$why $A = \frac{1}{2} A + \frac{1}{2} A^\top $ is not always true?

Prove that if $\eta = \log(\frac{\phi}{1-\phi})$ then $\phi = \frac{1}{1+e^{-\eta}}$

Detail in the proof that eigenvectors are orthogonal

Computation of $(\textbf{u}\cdot \nabla)\textbf{u}$ in the Navier stokes equation: inner or outer product?

show that $\textbf{u} = \textbf{v}$ if $\langle \textbf{u}, \textbf{h}\rangle + o(\|h\|) = \langle \textbf{v}, \textbf{h}\rangle + o(\|h\|)$

Linear algebra: Minimizing a quadratic form under linear constraints

Show that A-conjugate directions are are linearly independent.

How should I know that $C^3 - 2 C + 1$ factors as $(C-1)\left(\left(C+\frac12\right)^2-\frac54\right)$?

Laplace equation: What is the difference between divergence operator and gradient operator both represented by $\nabla$? (in wikipedia article)

Taylor approximation of cos function

how fit a model with data following asymptotic / sigmoid pattern

Calculate the Eigenvalue of a 3x3 matrix

LU Decomposition: difference between between hand calculation and solver?

Line integral in a vector field

vector field out of a sphere

what is the significance of $\kappa$ in the proof of inconditional stability of the Crank-Nicolson scheme

Exercise using the derivation of the Euler-Lagrange equation

Question about line integral

Computing the condition number of a matrix

Matrices - homogeneous system

18.02 MIT Multivariate calculus - Computing most rapid decrease using directional derivative

Finite difference - Explicit / Implicit / Crank Nicolson - Does the implicit method require the least memory?

Using Newton Raphson's method to solve a non-linear boundary value problem?

Identify $f$, $f'$, $u$ and $u'$ in an equation to use chain rule