xenon's user avatar
xenon's user avatar
xenon's user avatar
xenon
  • Member for 12 years, 10 months
  • Last seen more than a month ago
56 votes
6 answers
116k views

Getting the inverse of a lower/upper triangular matrix

41 votes
5 answers
51k views

Column Vectors orthogonal implies Row Vectors also orthogonal?

23 votes
5 answers
19k views

Show that $\operatorname{rank}(A+B) \leq \operatorname{rank}(A) + \operatorname{rank}(B)$

14 votes
5 answers
10k views

Determining if a quadratic polynomial is always positive

11 votes
1 answer
14k views

Why composite transformations are multiplied to the right side?

11 votes
3 answers
16k views

Reason for reversing the order when transpose and inverse of a group of matrices

8 votes
1 answer
23k views

Properties of a matrix whose row vectors are dependent

8 votes
2 answers
8k views

"Splitting" determinant of a matrix

6 votes
3 answers
8k views

$A^{T}A$ positive definite then A is invertible?

6 votes
2 answers
602 views

Will any value of a free variable satisfy a system of equation?

6 votes
1 answer
1k views

Getting the determinant value of the original matrix from its upper triangular matrix

6 votes
2 answers
3k views

Creating a matrix of rank r from r number of rank 1 matrices?

6 votes
4 answers
389 views

Given $A^2+cA+cI=0$, how to find inverse of $A+(c-1)I$?

5 votes
2 answers
12k views

How is diagonal matrices a subspace of upper triangular matrices?

5 votes
2 answers
5k views

Why eigenvectors basis then transformation matrix is $\Lambda$?

5 votes
2 answers
2k views

Deriving the inverse of $\mathbf{I}$+Idempotent matrix

5 votes
1 answer
46k views

In what situations should I use and not use a pooled estimator for $\hat{p}$

4 votes
1 answer
196 views

What are the $X_1, X_2, ..., X_n$ in the Sampling Distribution of $\bar{X}=\frac { 1 }{ n } \sum _{ i=1 }^{ n }{ X_{ j } } $?

4 votes
3 answers
260 views

How come the columns of a matrix can form its nullspace?

4 votes
3 answers
1k views

How to multiply a matrix of block matrices?

4 votes
1 answer
3k views

Finding normal vectors of polygons

3 votes
2 answers
2k views

Finding the column space from nullspace and particular solution

3 votes
2 answers
2k views

Proving $S+T$ is a subspace of $\mathbb{R}^{n}$

3 votes
1 answer
2k views

Deriving equation of plane from reduced row echelon form

3 votes
1 answer
16k views

How do I determine if the vectors lie on a plane in an $N\times N$ matrix?

3 votes
3 answers
3k views

What is an intuitive meaning of $E(\overline { X } )$ and $Var(\overline { X } )$?

3 votes
1 answer
24k views

Finding probability $P(X+Y < 1)$ with CDF

2 votes
1 answer
1k views

Find probabilities of winning in a modified version of Monty Hall Problem

2 votes
1 answer
2k views

Finding the probability of getting no successes in a Geometric Distribution

2 votes
1 answer
546 views

How can I find the expected value due to the trials instead of simply expected value of trials of a geometric distribution?