Find the determinant by using elementary row operations
I'm having a problem finding the determinant of the following matrix using elementary row operations. I know the determinant is -15 but confused on h...
Apr 14, 2026 1 VIEWS
Topic: General
5104 Articles 
Parking Functions and the Binomial Theorem
A parking function is a function $f: \{1, \ldots n\} \rightarrow \{1, \ldots n\}$ which has the property that the list $(f(1), f(2), \ldots f(n))$ can be ...
Apr 14, 2026 1 VIEWS
Why is this translation not a linear transformation? [closed]
From Linear map, the sixth example: The translation $x \rightarrow x+1$ is not a linear transformation. Why? What about $x \rightarrow x +dx$? Is this tra...
Apr 14, 2026 1 VIEWS
Expanding maps of the circle and their coding
A continuous smooth ($C^{10}$-smooth, for example) map $f:S^1\to S^1$ of the circle is called expanding if $\inf_{x\in S^1} f'(x) > 1 $. Here $S^1...
Apr 14, 2026 1 VIEWS
Express the statements using quantifiers
The statement : Every student in this class has taken exactly two mathematics classes at this school. My idea of answer : It should probably be using a bi...
Apr 14, 2026 1 VIEWS
Existence of non-trivial solutions for $Ax=0$
I would like to prove the following claim: For a square matrix $A$ there exists a non-zero vector $x$ such that $Ax=0$ if and only if $A$ is singular. Is ...
Apr 14, 2026 1 VIEWS
Where to go after calculus?
Ok this is a bit of an unanswerable question, but hopefully someone will answer. As I have been going through college & high school there has been a k...
Apr 14, 2026 1 VIEWS
Does this make sense what I have written? Prooving that $\{|x|,|y|\}$ is a norm
I tried to proove the following in the last post Show that the norm $||(x,y)||=max\{|x|,|y|\}$ where ||.|| is the norm and $(x,y) \in \mathbb{R}^{2}$ real...
Apr 14, 2026 1 VIEWS
Fourier representation for $\tan(x)$
Q: Which Fourier representation is suitable for $f(x) = \tan(x)$: Fourier trigonometric series, Fourier half-range expansion, or Fourier integral and why?...
Apr 14, 2026 2 VIEWS
What is this symbol $\int$ called?
Title says it all (I think). I'm betting it's something to do with Standard Integrals though. What is this symbol "$\int$" called?
Apr 14, 2026 1 VIEWS
How to connect 9 dots with 4 straight lines?
The segments can also cut each other. I have tried and tried but I can do it with 5 segments only.
Apr 14, 2026 1 VIEWS
Ways to choose 10 questions from a 13 divided into two sets
A test requires to answer 10 questions, choosing atleast 4 from each of Parts A and B. If there are 6 questions in Part A and 7 in Part B, in how many way...
Apr 14, 2026 1 VIEWS