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Mark
  • Member for 10 years, 7 months
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  • Milan, Italy
35 votes
1 answer
27k views

Geometric meaning of the determinant of a matrix

21 votes
3 answers
41k views

Eigenvalues of the sum of two matrices: one diagonal and the other not.

11 votes
1 answer
468 views

Sampling theorem.

10 votes
2 answers
579 views

Physical meaning of linear ODE $xy''+2y' + \lambda^2 x y = 0$

10 votes
1 answer
2k views

Use the definition of "topologically conjugate" to prove that $F(x)=4x^3-3x$ is chaotic.

9 votes
3 answers
1k views

Some method to solve $\int \frac{1}{\left(1+x^2\right)^{2}} dx$ and some doubts.

8 votes
2 answers
335 views

Solving the differential equation $x x''(t)=\frac{1}{t^3-t}$

7 votes
5 answers
608 views

Compute this limit of series: $\lim_{n\rightarrow \infty} \frac{1}{n^{3}}\sum_{k=1}^{n-1}k^2 $

7 votes
7 answers
589 views

The definition of "number"

6 votes
1 answer
2k views

Prove that the baker map $B(x)$ is chaotic.

6 votes
3 answers
4k views

Transversal intersection.

6 votes
2 answers
2k views

What's the sum of $\sum_{k=1}^{\infty} e^{-k(x-k)^{2}}$?

6 votes
0 answers
266 views

Continued fraction and double series.

6 votes
0 answers
86 views

Infer $Tf=\sum_{n=1}^\infty (f,f_n) f_n$ from frame condition.

6 votes
2 answers
114 views

Integration $\frac{1}{2\pi}\int_{-\pi}^{\pi}(x-a)^ke^{-i\omega x}dx, \ \ \ \ a\in\mathbb R$.

5 votes
1 answer
80 views

Solving $t^2=x(t) x'(t) t^3+x'(t)$

5 votes
2 answers
133 views

Solving differential equation $x''(t)=x^6$.

5 votes
3 answers
529 views

nth derivative cardinal sine function.

5 votes
1 answer
313 views

Sum of the series $\sum_{k=1}^\infty (-1)^k \frac{2z}{k^2 \pi^2-z^2}\cos kt$

5 votes
3 answers
836 views

Calculate $ \int_\gamma \frac{1}{z-i}dz $

5 votes
1 answer
371 views

Divisibility of $2^n - 1$ by $2^{m+n} - 3^m$.

5 votes
3 answers
577 views

What's the sum of $\sum \limits_{k=1}^{\infty}\frac{t^{k}}{k^{k}}$?

5 votes
2 answers
275 views

Calculate $\int f(x) f''(x)dx$

5 votes
2 answers
554 views

Computing $\lim_{n\rightarrow \infty} \frac{1+\sqrt{2}+\sqrt[3]{3}+\cdots+\sqrt[n]{n}}{n}$.

5 votes
1 answer
700 views

What is the difference between high dimensional and low dimensional chaos?

5 votes
1 answer
87 views

The role of constant of integration

4 votes
0 answers
250 views

Calculate or evaluate double trigonometric integral

4 votes
2 answers
2k views

Matrices restricted to a subspace

4 votes
2 answers
432 views

Eigenvalues of Matrix Product.

4 votes
1 answer
57 views

References for $\delta(x-a)=\frac{1}{2\pi}\sum_{k=-\infty}^{+\infty}e^{i k(x-a)}$

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