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cr001
  • Member for 8 years, 10 months
  • Last seen this week
8 votes
3 answers
359 views

Is it possible to define a function $f$ from positive real to positive real such that $f(f(x)) = {1 \over x}$

6 votes
2 answers
110 views

Set of numbers with interesting property

5 votes
1 answer
205 views

How to prove a tiling of a hexagon must form a 3D cubic stack?

4 votes
1 answer
255 views

Is it true that $\angle ACK=\angle BCL$ in a circle?

3 votes
1 answer
85 views

Is there any situation where the derivative ${ dy \over (dx)^2 }$ makes sense?

3 votes
1 answer
220 views

Imposter solution for$ \sqrt{2x+15}-6=x$

3 votes
1 answer
120 views

Theory about infinity [closed]

2 votes
1 answer
84 views

Expected value: what is wrong with my reasoning?

2 votes
1 answer
192 views

Why the equation $E(X \mid X=1000) = 1000$ is false, intuitively?

1 vote
0 answers
39 views

Matrix characteristic polynomial: is there a fast way to verify?

1 vote
2 answers
154 views

Why $x^4+x=y^2+y$ has only a finite number of integer solutions?

1 vote
1 answer
98 views

Does $a≠b≠c$ imply $c≠a$?

1 vote
1 answer
455 views

Function for representing non-radical algebraic number

1 vote
0 answers
289 views

Counter-intuitive Nash Equilibrium. Can anyone explain why this happens?

1 vote
0 answers
197 views

Variant of the Two Envelopes Problem

1 vote
0 answers
78 views

Munkres Topology Lemma 7.2 confusion

1 vote
3 answers
1k views

Intuition behind open set in topology

1 vote
1 answer
38 views

Capturing the "antonym phrase" concept in Formal Logic

0 votes
0 answers
21 views

Complex numbers: what is the formal name for the graph representing all points after applying a function/transformation?

0 votes
2 answers
61 views

Prove $t^{1\over t-1}$ is rational only when $t=2$ in the context of solving $x^y=y^x$ where $x\neq y$

0 votes
1 answer
436 views

Is there a direct bijective mapping between triangulation and parenthesis grouping?