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Cure
  • Member for 10 years, 10 months
  • Last seen more than 1 year ago
13 votes
3 answers
7k views

Is $R$ a PID if every submodule of a free $R$-module is free?

12 votes
4 answers
1k views

Double integral over a region

11 votes
2 answers
7k views

Proving a metric induces the product topology

10 votes
2 answers
483 views

When the mathematical community consider the inclusion of a new axiom?.

8 votes
4 answers
36k views

Finding volumes — when to use double integrals and triple integrals?

8 votes
0 answers
1k views

Proving that $f:U\to\mathbb{R}^n$ differentiable is an open map when $\det \operatorname{J}f(a) \neq 0$

8 votes
4 answers
2k views

Solving $x\frac{\partial u}{\partial x} + y\frac{\partial u}{\partial y }=1$

7 votes
0 answers
1k views

Cardinal of a linearly independent subset of $R$-module

7 votes
2 answers
17k views

Find the volume between two surfaces

6 votes
1 answer
3k views

Finding the volume inside an elyptical cylinder and a sphere

6 votes
1 answer
298 views

Prove $\lim_{n\rightarrow \infty}\left(\sup_{\theta\in \Theta}\left| \frac{1}{n}\sum_{i=1}^n f(X_i,\theta)-E(f(X,\theta)) \right|\right)=0$

5 votes
1 answer
111 views

Find $\alpha$ such that the given point is critical for a implicitly defined funtion.

5 votes
2 answers
3k views

Show that the given function is a diffeomorphism

5 votes
1 answer
809 views

What does it means that sequences characterize closed sets and functions?

5 votes
1 answer
2k views

Isomorphism and cyclic modules

5 votes
1 answer
983 views

Stuck trying to prove that $e^{-x^{-2}}$ is $C^{\infty}$ [duplicate]

5 votes
1 answer
2k views

Prove $\cos x = \frac{8}{\pi}\sum_n \frac{n\sin 2nx}{4n^2-1}$ with Fourier series

5 votes
2 answers
494 views

Product of three primes that is a square modulo 389

4 votes
1 answer
2k views

Prove that maximal solutions are defined in $\mathbb{R}$

4 votes
1 answer
753 views

Is $[0,1]^{[0,1]}$ Hausdorff and first-countable?

4 votes
2 answers
455 views

Proving that $\mathrm{card}(2^{\mathbb{N}})=\mathrm{card}(\mathbb{N}^\mathbb{N})$

4 votes
1 answer
1k views

Solving exercise with Leibniz rule

4 votes
2 answers
119 views

Do roots of $z=1$ add up to 0?

3 votes
2 answers
290 views

If $A\simeq\prod A_i$ then $\sum e_i=1$

3 votes
2 answers
14k views

Fourier transform of $f (x)=(1-|x|)\,\mathbf 1_{|x| < 1}$

3 votes
1 answer
112 views

What does $\langle\overline{4}\rangle$ mean?

3 votes
1 answer
284 views

How many conjugates cycles are in a cycle?

3 votes
2 answers
596 views

Double integral -- tricky?

3 votes
1 answer
89 views

Are these definitions equivalent for a subbasis of the product space?

3 votes
2 answers
73 views

Why this function defines a bijection?

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