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hengxin
  • Member for 9 years, 8 months
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1539 votes
86 answers
583k views

Visually stunning math concepts which are easy to explain

  • 821
1212 votes
26 answers
127k views

Is $\frac{\textrm{d}y}{\textrm{d}x}$ not a ratio?

  • 15.1k
514 votes
22 answers
84k views

What are imaginary numbers?

340 votes
11 answers
211k views

What is the importance of eigenvalues/eigenvectors?

  • 5,129
265 votes
6 answers
143k views

What is the practical difference between a differential and a derivative?

  • 2,651
178 votes
27 answers
17k views

Proving the identity $\sum_{k=1}^n {k^3} = \big(\sum_{k=1}^n k\big)^2$ without induction

149 votes
28 answers
21k views

Simple theorems that are instances of deep mathematics

113 votes
25 answers
22k views

Different ways to prove there are infinitely many primes?

112 votes
8 answers
34k views

Are there real world applications of finite group theory?

  • 26.1k
102 votes
20 answers
11k views

What are some examples of mathematics that had unintended useful applications much later?

93 votes
23 answers
9k views

What are Your Favourite Maths Puzzles?

  • 3,325
92 votes
30 answers
50k views

Best Maths Books for Non-Mathematicians [closed]

  • 1,928
80 votes
9 answers
63k views

What is the meaning of the third derivative of a function at a point

  • 1,073
80 votes
12 answers
23k views

The Monty Hall problem

58 votes
4 answers
5k views

Why can we use induction when studying metamathematics?

  • 1,286
53 votes
11 answers
34k views

Video lectures on Real Analysis?

  • 18.8k
51 votes
1 answer
3k views

Identity for simple 1D random walk

  • 271k
40 votes
6 answers
69k views

Combination of smartphones' pattern password

  • 525
35 votes
1 answer
15k views

Chinese Remainder theorem with non-pairwise coprime moduli

  • 4,260
29 votes
5 answers
2k views

A probabilistic game with balls and urns

  • 56.8k
28 votes
4 answers
5k views

Intuition about the second isomorphism theorem

  • 24.4k
26 votes
7 answers
8k views

Applications of the Isomorphism theorems

  • 1,927
23 votes
5 answers
4k views

Examples of non-obvious isomorphisms following from the first isomorphism theorem

18 votes
4 answers
2k views

What is the smallest cardinality of a Kuratowski 14-set?

  • 3,132
16 votes
2 answers
4k views

For $G$ a group and $H\unlhd G$, then $G$ is solvable iff $H$ and $G/H$ are solvable?

  • 21.7k
16 votes
3 answers
1k views

Approximating $100!$

15 votes
4 answers
2k views

Best way of introducing determinants in a linear algebra course

  • 2,726
13 votes
4 answers
3k views

Why the axioms for a topological space are those axioms?

  • 24.4k
9 votes
2 answers
6k views

What does the isomorphism $G / Z(G) \cong \text{Inn}(G)$ mean?

  • 3,437
7 votes
2 answers
761 views

How to prove that this set is closed?

  • 7,700