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Jill Clover
  • Member for 9 years, 9 months
  • Last seen more than a month ago
187 votes
7 answers
134k views

How to intuitively understand eigenvalue and eigenvector?

27 votes
5 answers
46k views

What is degree of freedom in statistics?

21 votes
1 answer
3k views

How to understand the spectral decomposition geometrically?

20 votes
2 answers
43k views

What is the difference between continuous derivative and derivative?

18 votes
6 answers
3k views

Can an algorithm be part of a proof?

16 votes
2 answers
9k views

What is the difference between open ball and neighborhood in real analysis?

12 votes
1 answer
919 views

How to geometrically interpret $\sum^{p}_{1}\lambda_{i}(A)=\operatorname{tr}(A)$?

9 votes
2 answers
17k views

Does the product of two invertible matrix remain invertible?

8 votes
2 answers
3k views

Why do people use "K" to represent a complete graph?

6 votes
2 answers
361 views

Why $\sigma_{\bar{x}}=\frac{\sigma}{\sqrt{n}}$

6 votes
3 answers
6k views

If $ A$ is open and $ B$ is closed, is $B\setminus A$ open or closed or neither?

6 votes
4 answers
3k views

How to find limit of a sequence defined by recurrence formula

5 votes
3 answers
3k views

Soft question: Why freshmen feel linear algebra is abstract?

5 votes
4 answers
6k views

Which letter is not homeomorphic to the letter $C$?

5 votes
2 answers
628 views

How to understand Markov property?

5 votes
2 answers
9k views

What's the relationship between interior/exterior/boundary point and limit point?

4 votes
3 answers
23k views

How to show a set is closed.

4 votes
1 answer
74 views

Prove $n$-th derivative of a real function at $0$ is always $0$

4 votes
3 answers
325 views

Can $11^{13}-1$ be divided exactly by 6?

4 votes
1 answer
3k views

How to prove in a graph $G$, its incidence matrix $A$ is totally unimodular if and only if $G$ is a bipartite graph?

4 votes
2 answers
2k views

How many distinct real root does the equation $x^{4}-x^{3}\cdot\sin(x)-x^{2}\cdot\cos(x)=0 $ have?

4 votes
2 answers
221 views

Maps $g$ maps $\left\{1,2,3,4,5\right\}$ onto $\left\{11,12,13,14\right\}$ and $g(1)\neq g(2)$. How many g are there.

4 votes
2 answers
9k views

How many solutions does $\cos(97x)=x$ have?

3 votes
3 answers
2k views

How many additive abelian groups $G$ of order 16 have the property such $x+x+x+x=0$

3 votes
2 answers
302 views

Calculate $\int_{0}^{\frac{\pi}{2}}\frac{\sin^{3}(t)}{\sin^{3}(t)+\cos^{3}(t)}dt$ by hands

3 votes
0 answers
190 views

Show a function is integrable on [0,1]

3 votes
1 answer
229 views

Which one is correct? $(n/2)$nd or $(n/2)$th? [closed]

2 votes
2 answers
73 views

Show $f$ attains local minimum at a given point

2 votes
1 answer
1k views

What's the relationship between Cauchy-Schwarz Inequality and Extended Cauchy-Schwarz Inequality?

2 votes
2 answers
160 views

Let $f'(0)=f''(0)=1$, $f^{(12)}(x)$ is differentiable and $g=f(x^{10})$ What's the value of $g^{(11)}(0)$?