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Freeman
  • Member for 12 years, 11 months
  • Last seen more than 3 years ago
  • United Kingdom
60 votes
4 answers
15k views

Would a proof to the Riemann Hypothesis affect security?

56 votes
5 answers
30k views

Why are maximal ideals prime?

52 votes
4 answers
41k views

Proving the trace of a transformation is independent of the basis chosen

45 votes
6 answers
27k views

Why is a finite integral domain always field?

31 votes
3 answers
10k views

If a field $F$ is such that $\left|F\right|>n-1$ why is $V$ a vector space over $F$ not equal to the union of $n$ proper subspaces of $V$

28 votes
4 answers
21k views

Proving $2,3,1+\sqrt{-5}$ and $1-\sqrt{-5}$ are irreducible in $\mathbb{Z}[\sqrt{-5}]$

26 votes
4 answers
38k views

What are the fields with 4 elements? [closed]

18 votes
1 answer
5k views

Show that two states in the same communicating class of a Markov chain must have the same period

14 votes
3 answers
2k views

What contour should be used to evaluate $\int_0^\infty \frac{\sqrt{t}}{1+t^2} dt$

14 votes
2 answers
10k views

How do you find all $n$ such that $\phi(n)|n$

11 votes
2 answers
15k views

What values makes this Markov chain aperiodic?

10 votes
1 answer
2k views

Solving the heat equation with Fourier Transformations

10 votes
4 answers
88k views

Finding the Laurent series of $f(z)=1/((z-1)(z-2))$

9 votes
1 answer
16k views

If $X$ is a Poisson distribution with mean $\lambda$ how is $X^2$ distributed?

8 votes
1 answer
1k views

Evaluate $\sum\limits_{n=0}^\infty \frac{1}{4n^2+1}$ by using complex contour integration

7 votes
2 answers
3k views

Calculating the residues of $f(z)=\frac{e^{az}}{1+e^z}$

7 votes
2 answers
181 views

Proving: $2n (\sum_{i=1}^{2n} a_i^2) \geq (\sum_{i=1}^{2n} a_i)^2+(\sum_{i=1}^{2n} a_i (-1)^i)^2$

7 votes
2 answers
4k views

What is the radius of convergence of $\sum z^{n!}$?

7 votes
1 answer
243 views

How to prove $\nabla\cdot \vec{B}=0 \Rightarrow \exists \vec{A}:\vec{B}=\nabla \times \vec{A}$

7 votes
2 answers
246 views

What is the value of $x$ such that $\frac{\text{d}^2y}{\text{d}x^2}=0$ where $\frac{\text{d}y}{\text{d}x}=-ae^{-bx}y-cy+d$?

6 votes
3 answers
3k views

For a general plane, what is the parametric equation for a circle laying in the plane

6 votes
4 answers
532 views

How to derive the approximation $\tan(x)\simeq \frac{x}{1-x^2/3}$

6 votes
3 answers
23k views

How to find all the solutions to cos$(z)=0$

6 votes
2 answers
3k views

Prove that a sum of projections is a projection iff they are orthogonal, if the characteristic of the space is not $2$

5 votes
5 answers
5k views

Modular Arithmetic question, possibly involving Chinese remainder theorem

5 votes
2 answers
1k views

How to solve a 2D ODE system of the form $\frac{\text{d}\vec{x}}{\text{d}t}=(M-\Delta e^{-\lambda t})\vec{x}+\vec{x}_0$

5 votes
1 answer
900 views

Solving Laplace's equation in a sphere with mixed boundary conditions on the surface.

5 votes
1 answer
100 views

How to prove $\oint_\Gamma \nabla\theta\cdot\vec{dr}=\pm2\pi $ around a phase singularity/over a cut

4 votes
1 answer
4k views

Contour integration of $\int_{-\infty}^{\infty}e^{iax^2}dx$

4 votes
4 answers
128 views

What is $\lim_{\alpha\rightarrow0} \left(\alpha\log^2{\alpha}\right)$?

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