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Miguel Mora Luna's user avatar
Miguel Mora Luna's user avatar
Miguel Mora Luna's user avatar
Miguel Mora Luna
  • Member for 12 years, 2 months
  • Last seen more than 4 years ago
67 votes
7 answers
146k views

Is the sum and difference of two irrationals always irrational?

57 votes
8 answers
25k views

How I can prove that the sequence $\sqrt{2} , \sqrt{2\sqrt{2}}, \sqrt{2\sqrt{2\sqrt{2}}}$ converges to 2?

22 votes
2 answers
10k views

What is the importance of definite and semidefinite matrices?

20 votes
3 answers
27k views

The boundary is a closed set

20 votes
2 answers
19k views

Prove that the composition of differentiable functions is differentiable.

12 votes
5 answers
3k views

Is it true that $\lvert \sin z \rvert \leq 1$ for all $z\in \mathbb{C}$?

6 votes
3 answers
14k views

Calculate $\lim_{n\to{+}\infty}{(\sqrt{n^{2}+n}-n)}$ [duplicate]

6 votes
1 answer
8k views

Continuous images of compact sets are compact

6 votes
1 answer
2k views

Is my solution correct to prove that $f (x) = 0$ for all $x \in [a, b]$? [duplicate]

5 votes
3 answers
329 views

Finding a topology on $ \mathbb{R}^2 $ such that the $x$-axis is dense

5 votes
2 answers
710 views

Why demonstrations are important in mathematics? [closed]

4 votes
3 answers
304 views

How do I prove that $X$ is connected?

4 votes
3 answers
6k views

Under what circumstances is the discrete metric space separable?

4 votes
1 answer
2k views

If $f$ is analytic in a region and at every point either $f\,' = 0$ or$ f = 0$, then $f$ is constant

4 votes
1 answer
516 views

How do I prove that $\sin(π/2+iy)=1/2(e^{y}+e^{−y})=\cosh y$?

3 votes
3 answers
817 views

Divergence of the harmonic series and the Cauchy criterion imply $\lim_{n\to\infty} \sqrt[n]n=1$

2 votes
1 answer
152 views

Differences in how mathematical results are proved in the time of Euclid and in the twentieth century [closed]

2 votes
5 answers
1k views

If $f$ is continuous and $\int_0^1f(xt)dt=0$ for every $x $, then $f\equiv 0$

2 votes
0 answers
571 views

problem of uniform convergence of series

2 votes
3 answers
359 views

How was born the topology from Euclidean geometry?

2 votes
1 answer
1k views

How I can show that the point P (Miquel point) is in the circle formed by the centers of the other 4 circles?

2 votes
3 answers
1k views

What is the importance of integral domains?

2 votes
1 answer
4k views

Let the random point (X, Y ) be uniformly distributed on the triangle

2 votes
0 answers
341 views

sub-basis for a topology on the real line

2 votes
1 answer
352 views

$f+g$ is measurable no matter how it is defined at points where it has the form $\infty-\infty.$?

1 vote
1 answer
760 views

Why come to the conclusion that a Borel set is measurable?

1 vote
2 answers
274 views

How I can prove this? (fixed points of $f(x)=(x^3+1)/3$)

1 vote
1 answer
365 views

How I can justify that the residue is -1/2?

1 vote
1 answer
262 views

example of a positive function-riemann stieltjes integral

1 vote
1 answer
97 views

how evaluate $\int_{-1}^{1} z^{\frac{1}{2}}\, dz$?