Lee's user avatar
Lee's user avatar
Lee's user avatar
Lee
  • Member for 8 years, 3 months
  • Last seen more than a month ago
  • Hong Kong
4 votes

Prove all elements $x_n \geq \sqrt{2}.$

3 votes

Cayley-Hamilton theorem for symmetric positive definite matrix

3 votes
Accepted

Why there is two possible equals solution?

3 votes

Probability of same genes or cards.

2 votes
Accepted

How to solve for a trigonometric inequality $2\cos(2x)\cos(x)+\cos(2x)\gt0$

2 votes
Accepted

If all eigenvalues of $A$ are in unit disc then $A^n\to 0$

2 votes

Minimize $x^*(A+A^*)x$ such that $x^*A^*Ax=1$ and $x^*x=1$

2 votes

Proving that the arithmetic and geometric means of a collection of non-negative numbers lies between their minimum and maximum values

1 vote

Simplify (W + Y) (W' + X' + Y) (X' + Y' + Z')

1 vote
Accepted

\begin{array}{ll}\min\limits_{{x,y:\,yHx=1}} x^Txyy^T\end{array}

1 vote

Length of a side of a triangle with angle relations

1 vote
Accepted

What is the maximum value of $x^TAx$ subject to $x\in\{\pm1\}^n$?

1 vote
Accepted

Link between Hadamard's inequality for positive-definite matrices and general Hadamard's inequality

1 vote
Accepted

Convex function: optimization

1 vote

Find solutions for the equation $a^3 + b^3 = c^2$ in integers $c\geq b\geq a\geq1$

1 vote

Possible Jordan Canonical Forms

1 vote
Accepted

Divisibility in a Euclidean Domain

1 vote

Why is the trace of a hermitian matrix raised to an even power greater than or equal to 0?

1 vote

Integer solution of $abc=a+b+c+2$.

1 vote
Accepted

Generating symmetric Positive Definite Matrix from random vector multiplication yield singular matrix

1 vote

Control system problem

1 vote

Find the real numbers given their product

1 vote

Form of Jordan block

1 vote

Increasing the rank of null space matrix by real columns

1 vote

If the singular value decomposition $U\Sigma V^T$ has rank $r$ and $Q$ is semi-orthogonal, then $Q\Sigma V^T$ has rank $r$ as well

1 vote

Prove that $d^2=a^2+b^2+c^2-2[ab\cos B+bc\cos C+ac\cos(α)]$

1 vote

How many ways can 8 boxes be arranged taking 3 at a time?

1 vote

$4p+1$ is perfect cube, sum of all possible $p$ values?

0 votes
Accepted

Divide people to several groups

0 votes

Prove: A ⋂ (B+C) = (A ⋂ B) + (A ⋂ C)