114,735 reputation
7106211
bio website von-eitzen.de/math/tntrep.xml
location Bonn, Germany
age 48
visits member for 2 years, 1 month
seen 9 hours ago

I did study math and had a knack for it, but I am sooo out of that business now ...


Dec
5
comment Advice for proving with induction scenarios with multiple chances for using the hypothesis.
What choices do you mean? To take either $12^{n+1}+6^{2n+2}-3^{n+1}+120 = (12^n+2^{2n}-3^n+120)\cdot 12+(\ldots)$ or $12^{n+1}+6^{2n+2}-3^{n+1}+120 = (12^n+2^{2n}-3^n+120)\cdot 6^2+(\ldots)$ or ... as next step?
Dec
5
answered $a\in\mathbb C$ such that $a^n=1,a^m\neq 1\,(m=1,2,\ldots,n-1) $
Dec
4
answered Prove that set is arcwise-connected. Function $\mathbb{R}^3 \to \mathbb{R}^2$ with differential of rank $2$.
Dec
4
comment minimal field extension of Q($\sqrt[3] {2}$)
It looks like you described it quite fine
Dec
4
comment How can we prove this function must be linear?
The condition could just as well be written $\lim_{r\to 0}\frac{f(x-r)+f(x+r)-2f(x)}{r^2}=0$.
Dec
4
answered Finding the limit of $ \frac{1}{n}\sum_{k=1}^{n}\sqrt[k]{k} $
Dec
4
answered Why $\mathbb{N} \subset V_\omega$ and $Seq(\mathbb{N}) \subset V_\omega$?
Dec
4
answered A question about limit at infinity
Dec
4
answered Homomorphisms from $\mathbb{Z} \rightarrow S_3$.
Dec
4
answered Minimal Equivalence Relations
Dec
4
answered Proving if function is one to one
Dec
4
reviewed No Action Needed Word Problem Using elimination and/or substitution
Dec
4
reviewed No Action Needed Proving that two function coordinates of a parametric curve equals 1
Dec
4
reviewed No Action Needed How many 4 digit numbers can be made with exactly 2 different digits
Dec
4
comment Limit for $\lim _{n \to \infty}(n+2)^{2}\sin\frac{1}{n}$
Do you know that $\lim_{x\to0}\frac{\sin x}{x}=1$?
Dec
4
revised Limit for $\lim _{n \to \infty}(n+2)^{2}\sin\frac{1}{n}$
LaTeX finetuning
Dec
4
comment If a finite group $G$ is generated by two elements $x$ and $y$, then do $x$ and $xy$ also generate it?
@AWertheim Actually, the finiteness hypothesis is not needed as in the context of groups $\langle x,xy\rangle$ denotes the smallest group containing $x$ and $xy$, hence automatically contains $x^{-1}$.
Dec
4
comment Decide whether the following statements are true or false. If true, prove it. If false, provide a counterexample
Hint: What if $h$ is not onto (e.g. constant)?
Dec
4
awarded  trigonometry
Dec
3
reviewed Leave Open GCD (p+q,p-q) with distinct odd primes