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cambelot
  • Member for 10 years, 1 month
  • Last seen more than 6 years ago
19 votes
9 answers
54k views

Proof that the set of irrational numbers is dense in reals

9 votes
3 answers
6k views

Proof that arithmetic and geometric mean converge

9 votes
2 answers
4k views

Can a group be a union of three subgroups?

8 votes
3 answers
20k views

Show that Cov(X,Y)=Cov(X,E(Y|X)).

6 votes
1 answer
2k views

Application of Stein's Lemma to Calculate Moments of Normal (0,1)

4 votes
1 answer
3k views

Proof that the set of irrational numbers is dense in the reals

4 votes
1 answer
239 views

Studying for Abstract Algebra

4 votes
2 answers
3k views

Verification of Proof that if $G$ is not abelian $G/Z(G)$ is not cyclic

3 votes
5 answers
275 views

Compute $Z_{4}\times Z_{8}/\langle(1,2)\rangle$

3 votes
1 answer
2k views

Prove $|\det A| \leq \prod_{j=1}^n ||a_j||$

3 votes
1 answer
398 views

Correctness of proof that an ordered field S that has the supremum property also has the infimum property

3 votes
1 answer
11k views

Solving a 3x3 payoff matrix

3 votes
3 answers
2k views

How does one prove the Taylor's Theorem by the Cauchy's Mean Value Theorem?

3 votes
2 answers
2k views

Prove that the unity element in a subfield of a field must be the unity of the whole field

3 votes
3 answers
3k views

The sum of the elements in a field of at least three elements is 0

3 votes
2 answers
2k views

Prove that for $f,g\in F[x]$, where $F$ is an infinite field, if $f(a)=g(a)$ for infinitely many elements $a\in F$, then $f=g$

3 votes
2 answers
12k views

Find a formula for the nth Fibonacci Number [duplicate]

3 votes
5 answers
1k views

Find roots of $e^z=-3$ given that z=x+iy

3 votes
1 answer
3k views

Show that $\sum r^n \cos(nx)=r\cos(x)-r^2/(1-2r\cos(x)+r^2)$

2 votes
1 answer
975 views

Calculate $\sin(z)/(z+i)$ using Cauchy Integral Formula on region $|z+i|=3$

2 votes
1 answer
3k views

Assume |f(z)| is constant for all z in $\Omega$ then f is a constant function

2 votes
2 answers
248 views

Assume $f(z)=f(x+iy)=u(x,y)+iv(x,y)$ is holomorphic on $\Omega$. Prove that the Jacobian of Cauchy-Riemann components is $|f'(z)|^2$

2 votes
1 answer
169 views

Verification of Proof: Let $R$ be a ring of unity and $a \in R$ satisfy $a^2=1$. $S=\{ara \mid r \in R\}$ is a subring

2 votes
1 answer
356 views

Prove that $I=\{x \in R : ax=0\}$ is a subring of $R$

2 votes
0 answers
52 views

Prove that $\mathrm{Re}(z_1\overline{z_2})=|z_1||z_2|\;\mathrm{iff}\;\arg(z_1)-\arg(z_2)=2n\pi$, where $n\in\mathbb{Z}$.

2 votes
1 answer
73 views

Is this just asking for the Uniqueness of Limits? If not, how can you do this?

2 votes
2 answers
60 views

How would Intermediate Value Theorem be used in this question?

2 votes
1 answer
73 views

Real Analysis question dealing with Intermediate Value Theorem. Or is there another way to do it?

2 votes
0 answers
179 views

Gerschgorin Theorem singularity proof

2 votes
2 answers
130 views

Question about separation of variables

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