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trynalearn
  • Member for 6 years, 7 months
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37 votes
6 answers
14k views

Why isn't the area of a square always greater than the length of one of its sides?

8 votes
1 answer
424 views

On Cardinalities of Finite Sets

8 votes
2 answers
285 views

How Euler arrived at power series for $a^x$ and $\ln x$

4 votes
1 answer
195 views

Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?

4 votes
1 answer
88 views

Thue's proof of finitely many integer solutions to $x^2 - y^3 = c$

4 votes
1 answer
94 views

Show that $\int_1^x \log^kt\log^l\frac{x}{t} dt = xQ(\log x),$ where $Q(t)$ is a polynomial with leading term $l!t^k$

4 votes
1 answer
113 views

Why is $\frac{|1 - e^{2 \pi i \alpha N}|}{|1 - e^{2 \pi i \alpha}|} \leq \frac{\sin(\pi \alpha N)}{\sin(\pi \alpha)} \leq \frac{1}{||\alpha||}$?

3 votes
2 answers
270 views

Circle geometry problem (find an angle in a figure)

3 votes
2 answers
304 views

Group of homomorphisms from $\mathbb{R}/\mathbb{Z}$ to itself

3 votes
1 answer
1k views

A prime ideal $\mathbf{p}$ "lying above" a prime p

3 votes
1 answer
260 views

Distribution of types of numbers in the real line

3 votes
1 answer
1k views

"Replacing" Calculus with Real Analysis [closed]

3 votes
1 answer
2k views

Describing affine subspace

3 votes
1 answer
37 views

Group action on Grasmannian

2 votes
1 answer
41 views

2 "equivalent" definitions of $\mathbf{C}$-algebras.

2 votes
0 answers
137 views

4 linear equations in 4 variables with complex coefficients

2 votes
2 answers
2k views

The Commutator Subgroup $K$ of $G$ is the "smallest" subgroup such that $G/K$ is Abelian.

2 votes
1 answer
169 views

Show that $|v| + |v + w| + |w + z| + |2 + z|\ge 2$ for complex numbers $v,w,$ and $z$

2 votes
1 answer
751 views

proof about generators of a cyclic group

2 votes
1 answer
49 views

A simple complex number inequality

2 votes
2 answers
520 views

Counting time with a watch that pauses for 15 minutes every hour

2 votes
1 answer
55 views

Surjections commuting with the function $t:\mathbb N\to\mathbb N$, $t(n) = n+1$?

2 votes
1 answer
255 views

Constructing a normed space from a metric on a vector space.

2 votes
1 answer
815 views

Is the Natural numbers definition (recursively using empty set) Circular?

2 votes
1 answer
47 views

Proof involving rational functions on an elliptic curve

2 votes
0 answers
43 views

Are these two algebras isomorphic?

2 votes
1 answer
613 views

changes of coordinates (effect on points and curves)

1 vote
0 answers
182 views

An affine transformation, and its effect on a curve and a polynomial.

1 vote
0 answers
36 views

Suppose $G$ is a commutative group, and $H_1,H_2$ are subgroups, then $H_1H_2$ is a subgroup.

1 vote
1 answer
105 views

changes of coordinates, confusing book language.