Mathematics

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Jun 3, 2019 17:31
That's a better approach... Thank you very much... I got it :) @Semiclassical
Jun 3, 2019 17:18
I am a little confused right now why $\binom{5}{1} \cdot \binom{4}{2} \cdot$ is the number of rolls of the form 422xy up to permutation :/
Jun 3, 2019 17:12
Ah I see... $binom{5}{1} \cdot \binom{4}{2} \cdot \cdot (1/6)^3*(4/6)^2$ is the probality , right?
Jun 3, 2019 17:11
or am I wrong?
Jun 3, 2019 17:11
the results of the other two rounds where we do not get 2 or 4
Jun 3, 2019 17:10
So the probability is $\binom{5}{1} \cdot \binom{4}{2} \cdot \cdot (1/6)^3*(4/6)^2 * 4^2$ , right? @Semiclassical
Jun 3, 2019 17:02
$\binom{5}{1} \cdot \binom{4}{2} \cdot$ is the probility so far, right? @Semiclassical
Jun 3, 2019 16:59
The probability of 2 {2} and 1 {4} is $5 \cdot \frac{1}{6}+4 \cdot 2 \cdot \frac{1}{6}$, right? @Semiclassical
Jun 3, 2019 16:56
And then for the rest there are $3$ places @Semiclassical
Jun 3, 2019 16:50
$\binom{6}{2}$, right? @Semiclassical
Jun 3, 2019 16:49
So we pick the product 5*1/6*4/6*1/6*4/6*1/6, right?
Jun 3, 2019 16:46
But we aren't @Semiclassical
Jun 3, 2019 16:46
Why? @Semiclassical
Jun 3, 2019 16:45
we want 1 {4}, so the possibility of one round is $\frac{1}{6}$, we want 2 ${2}$, so the possibility is $\frac{1}{6} \cdot \frac{1}{6}$ and at the remaining rounds the probability is $\frac{4}{6}$ since we allow any number except than 2,4... am I right? @Semiclassical
Jun 3, 2019 16:43
Without restrictions, there are $6^5$ possible results, right? @Semiclassical
Jun 3, 2019 16:41
yes @Semiclassical
Jun 3, 2019 16:40
I assume that exactly 2 is meant @Semiclassical
Jun 3, 2019 16:37
Oh sorry, we roll it 5 times @Semiclassical
Jun 3, 2019 16:37
@Secret MaryStar is my sister :p
Jun 3, 2019 16:36
there are no other informations given @Semiclassical
Jun 3, 2019 16:35
Could you explain it further to me? @Semiclassical
Jun 3, 2019 16:34
hey @LeakyNun
do you know if I am right?
Jun 3, 2019 16:33
Hello!!!

Is the probability to get two {2} and one {4} when throwing a dice equal to $\frac{1}{6} \cdot \frac{1}{6} \cdot \frac{1}{6} \cdot \frac{4}{6} \cdot \frac{4}{6} \cdot \frac{4}{6}$ ?
May 5, 2019 08:58
Hello @ThomasKlimpel@Astyx Do you have an idea?
May 5, 2019 08:34
If a rent a car company has 700 cars and the average per rental is 9 days, then we muliply $2.3$ by $700$ in order to find the expected number of bookings per month.

So the expected number of bookings is equal to $700 \cdot \frac{700}{9 \cdot 30} $, right ?

Why does this happen? Could you explain to me the formula?
May 5, 2019 08:32
Hello, I have a question!
Dec 9, 2018 20:52
Could you give me a hint?
Dec 9, 2018 20:52
Let $f: \mathbb{R} to \mathbb{R}$ with the properties: $f(x)>0, \forall x \geq 0$, $f$ is decreasing and $f'(0)=0$. I want to prove that $f''(x)=0$ for some $x>0$.
Dec 9, 2018 20:52
Hello
Dec 1, 2018 22:29
Nice, thank you :) @Axoren
Dec 1, 2018 21:34
So we choose $\epsilon'=\epsilon |a_2-a_1|$ and and we have that $\forall \epsilon'>0$ $\exists N:=m_0$ so that when $n, m \geq N$ then $|a_n-a_m| \leq \epsilon'$.

And thuis holds since $\epsilon$ is arbitrary and so we can get any number , right? @Axoren
Dec 1, 2018 21:31
do we pick $\epsilon'=\epsilon |a_2-a_1|$ ?
Dec 1, 2018 21:29
We then have that for $m \geq m_0$, $|a_n-a_m| \leq \epsilon |a_2-a_1|$
Dec 1, 2018 21:28
@Axoren Using the definition, we have from $\lim_{m \to +\infty} \frac{\theta^{m-1}}{1-\theta}=0$ that $\forall \epsilon>0$, $\exists m_0 \in \mathbb{N}$ such that $\forall m \geq m_0$, $\left| \frac{\theta^{m-1}}{1-\theta}\right|< \epsilon$.

How do we use this?
Dec 1, 2018 20:41
It is known that for $0<a<1$, $\lim_{n \to +\infty} a^n=0$, not? @Axoren
Dec 1, 2018 20:34
Do we pick $m \to +\infty$ ? @Axoren
Dec 1, 2018 20:29
@Axoren so $\forall \epsilon:=\frac{\theta^{m-1}}{1-\theta} |a_2-a_1|$ $\exists N:=m-1$ so that when $n, m \geq m-1$ then $|a_n-a_m|\leq \epsilon$.

thus $(a_n)$ is Cauchy and it converges, right?
Dec 1, 2018 20:10
How do we show that it's Cauchy? $(x_n)$ is Cauchy if $\forall \epsilon>0$, $\exists N$ so that when $n,m \geq N$ we have that $|a_n-a_m|\leq \epsilon$.


In our case, we have a specific number, say b, such that $|a_n-a_m| \leq b$... @AkivaWeinberger
Dec 1, 2018 20:00
Does anyone have an idea?
Dec 1, 2018 20:00
Let $0<\theta<1$ and a sequence $(a_n)$ such that

$|a_n-a_m| \leq \frac{\theta^{m-1}}{1-\theta} |a_2-a_1|$ for all $n>m$.

How can we show that $(a_n)$ converges?
Dec 1, 2018 16:56
Hello @Astyx @Semiclassical

Do you have an idea?
Dec 1, 2018 16:55
Let $0<\theta<1$ and a sequence $(a_n)$ such that

$|a_n-a_m| \leq \frac{\theta^{m-1}}{1-\theta} |a_2-a_1|$ for all $n>m$.

How can we show that $(a_n)$ converges?
Dec 1, 2018 16:55
Hello!!!
Oct 13, 2018 20:08
@Alucard I see, thank you :)
Oct 13, 2018 08:08
Hey @LeakyNun
Do you maybe have an idea?
Oct 13, 2018 08:03
Hello!!!

Does it hold that $a^n(-1)^{n^2}$ converges iff $a^n$ converges?
Oct 7, 2018 08:33
Great... Thank you :)
Oct 7, 2018 08:31
That it's correct? :p @Secret
Oct 7, 2018 08:30
We have that $1 \pm \frac{1}{n} \leq 1+\frac{1}{n}\leq 1+\frac{1}{2}=\frac{3}{2}$.

Thus $\frac{3}{2}$ is the supremum of the set. Right?
Oct 6, 2018 09:48
How do we get that the odd subsequence converges to 0? @Secret