• Today, 10:41
Here is this week's POTW: A charge $-q_1$ is located at the origin of a $y$-axis and a charge $-q_2$ is located at $y=d$. At what point along...
0 replies | 9 view(s)
• Today, 10:40
Congratulations to the following members for their correct submission: kaliprasad My solution is as follows: For the entire system...
1 replies | 50 view(s)
• Today, 03:58
Krylov replied to a thread Open cover in Analysis
Yes, you have the right intuition. Now you need to show that for any given $n \in \mathbb{N}$ the two equalities \ have at least one solution...
3 replies | 48 view(s)
• Yesterday, 21:50
I am reading Paul E. Bland's book "Rings and Their Modules" ... Currently I am focused on Section 3.2 Exact Sequences in ModR ... ... I need...
1 replies | 56 view(s)
• Yesterday, 15:53
mathmari replied to a thread Open cover in Analysis
I think that it holds that there is for every $n \in \mathbb{N}$ an $0 < x < 1$ such that $\frac{1}{n} \in \left(\frac{x}{2},\frac{3x}{2}\right)$,...
3 replies | 48 view(s)
• Yesterday, 15:42
Hello and welcome to MHB! :D We ask that our users show their progress (work thus far or thoughts on how to begin) when posting questions. This...
1 replies | 59 view(s)
• Yesterday, 15:09
Krylov replied to a thread Open cover in Analysis
That is right. Yes. In some more detail: You need to check if for every $a \in A$ there exists an interval $I$ in the collection $S_1$...
3 replies | 48 view(s)
• Yesterday, 14:43
mathmari started a thread Open cover in Analysis
Hey!! :o Let $\mathbb{R}$ provided with the metric $d(x,y)=|x-y|$. I want to check if the collections of sets S_1=\left \{\left (\frac{x}{2},...
3 replies | 48 view(s)
• Yesterday, 09:31
I like Serena replied to a thread Right triangle. in Geometry
Google translates triangle as sankakkei. And searching for sankakkei shows that this word is also used for a three dimensional puzzle of triangles....
19 replies | 193 view(s)
• April 24th, 2018, 13:16
Hi Tony. I recommend you read up on our guidelines for posting challenge problems, found here.
1 replies | 47 view(s)
• April 24th, 2018, 07:48
Not just for the next term, but for the whole sequence! In fact, your prediction and mine both say that the $(n+1)$th term minus the $n$th term is...
9 replies | 141 view(s)
• April 24th, 2018, 06:54
My own best guess was to look at the differences: $\frac 13, \frac 16, \frac 1{10}$. The next difference might be $\frac 1{15}$, although it does...
9 replies | 141 view(s)
• April 24th, 2018, 06:37
Hi hm2018April, and welcome to MHB! Mathematicians hate problems like this, because there usually isn't a single, "correct" solution. You need to...
9 replies | 141 view(s)
• April 24th, 2018, 03:57
Hello hm2018April and welcome to MHB! :D We ask that our users show their progress (work thus far or thoughts on how to begin) when posting...
9 replies | 141 view(s)
• April 24th, 2018, 01:48
Thanks GJA ... Appreciate your help... Peter
2 replies | 39 view(s)
• April 23rd, 2018, 23:24
I am reading Paul E. Bland's book "Rings and Their Modules" ... Currently I am focused on Section 3.2 Exact Sequences in \text{Mod}_R ... ... ...
2 replies | 39 view(s)
• April 23rd, 2018, 15:52
I like Serena replied to a thread Special Relativity in Physics
It's the other way around.
11 replies | 135 view(s)
• April 23rd, 2018, 15:26
I like Serena replied to a thread Right triangle. in Geometry
For the record, something like that is called a sangaku. A drawing that exhibits a proof, without any words, expressions, or symbols. Admittedly my...
19 replies | 193 view(s)
• April 23rd, 2018, 15:04
I like Serena replied to a thread Right triangle. in Geometry
You mean just drawings? (Wondering) Something like this: \begin{tikzpicture} %preamble \usetikzlibrary{arrows} \def\a{sqrt(17)} ...
19 replies | 193 view(s)
• April 23rd, 2018, 14:00
A basic-open element is a finite intersection of sets of the form $\pi_k^{-1}(O_k)$ where $O_k$ is any subset of $\{0,1\}$ and $\pi_k$ is the $k$th...
5 replies | 99 view(s)
• April 23rd, 2018, 13:37
I like Serena replied to a thread Right triangle. in Geometry
To be honest, I only used trigonometry because it means I have to use fewer words to explain those ratios! (Rofl)
19 replies | 193 view(s)
• April 23rd, 2018, 13:31
Krylov replied to a thread Algebra II in Pre-Algebra and Algebra
Hello and welcome, This is not a question, but rather a symbolic expression. Would you like the expression simplified? One way is to note that...
1 replies | 56 view(s)
• April 23rd, 2018, 13:20
I like Serena replied to a thread Right triangle. in Geometry
Trigonometry is only used in the first step. We can replace it with non-trigonometry by observing that triangles ABC and ACD are similar, meaning...
19 replies | 193 view(s)
• April 23rd, 2018, 13:18
Yes, first do what post #2 says. You can make it a bit simpler for yourself by restricting to basic-open covers: Show that every cover consisting...
5 replies | 99 view(s)
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