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• Today, 11:28
Here is this week's POTW: ----- The number $2^{29}$ has exactly 9 distinct digits. Find the missing digit. ----- Remember to read the...
0 replies | 10 view(s)
• Today, 11:03
Congratulations to the following members for their correct solution:): 1. MarkFL 2. castor28 3, kaliprasad Solution from MarkFL: WLOG, I...
1 replies | 126 view(s)
• Today, 10:46
Correct. For a 2x2 system it's indeed easiest to calculate and apply $A_{2h}^{-1}$. (Nod) Yes. The result of applying the 2-grid method...
24 replies | 510 view(s)
• Today, 09:19
As I understand it, we should: 1. Apply the damped Jacobi method twice on the fine grid. 2. Switch to the residue on the coarse grid. 3. Solve for...
24 replies | 510 view(s)
• Today, 00:02
You wound up with $x^2\sin(x)$ on the RHS before integrating, but it should be $x\sin(x)$. :)
1 replies | 26 view(s)
• Yesterday, 19:23
When you multiply through by $\mu(x)$, you should have: \frac{d}{dx}(\sin(x)y)=2 And then integrate: \sin(x)y=2x+c_1 ...
2 replies | 33 view(s)
• Yesterday, 16:29
Hmm... doesn't the solution break down at $x=2$? (Wondering) The initial value problem gives us solutions up to $x=2$, which is a singularity....
2 replies | 73 view(s)
• Yesterday, 16:26
I think it's not quite correct yet. When taking another derivative, we get different terms don't we? (Thinking) And additionally we get another...
25 replies | 423 view(s)
• Yesterday, 16:24
I've looked up the greedy algorithm and I think your approach is correct. Where did you get the specific $5$ meters though? Shouldn't it be $k$...
3 replies | 61 view(s)
• Yesterday, 16:16
It looks correct to me so far. (Thinking) Did you intentionally pick the $I_h^{2h}$ that does not use a weighed average? (Wondering) ...
24 replies | 510 view(s)
• Yesterday, 04:45
As $\zeta_n^{}$ is closed under multiplication, $\zeta_n^{}\subset\zeta_n^{}$. On the other hand, as $1\in\zeta_n^{}$, $\zeta_n^{}\subset\zeta_n^{}$....
1 replies | 60 view(s)
• June 19th, 2018, 19:21
Towards the end, when you divide through by $x$, you want: y(x)=\frac{e^x}{x}+\frac{c}{x} You mistakenly divided the constant by $e^x$.
1 replies | 39 view(s)
• June 19th, 2018, 15:31
Yes, but you used it on the original ODE, not the one in standard linear form. :)
4 replies | 87 view(s)
• June 18th, 2018, 14:11
Yes. And it also assumes we take $\nu=2$ steps with the damped Jacobi method. (Nod) It's not quite clear from the text to me. With a choice...
24 replies | 510 view(s)
• June 18th, 2018, 12:19
We can freely choose to use $\omega=2/3$ or a different $\omega$, or not use the damped Jacobi method at all. The chapter explains that it's giving...
24 replies | 510 view(s)
• June 18th, 2018, 06:19
Thanks steenis ... No worries at all ... Thanks for all your help ... Peter
10 replies | 214 view(s)
• June 18th, 2018, 06:04
Thanks Steenis ... That proof seems really clear ... Will work through it again shortly... Peter
4 replies | 80 view(s)
• June 18th, 2018, 05:18
Sorry Steenis ... I don't understand you ... Can you give me a hint as to what is wrong ...? Peter
10 replies | 214 view(s)
• June 18th, 2018, 04:51
Thanks steenis ... most helpful ... Can see that the short exact sequence \$0\rightarrow \text{ker } f \overset{i}{ \rightarrow}R^{(n)}...
10 replies | 214 view(s)
• June 18th, 2018, 01:22
======================================================================== Since I could not see any specific errors, I have completed the proof...
4 replies | 80 view(s)
• June 17th, 2018, 12:39
MarkFL replied to a thread [SOLVED] 2.2.3 de with tan x in Differential Equations
I can't imagine trying to use the internet on a telephone. I'm sorry scrolling on a telephone is such a chore...they should fix that.
8 replies | 113 view(s)
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### 24 Visitor Messages

1. Happy Birthday Opalg!! So glad you're here for another year. Have a great time celebrating.
2. Hi Opalg, happy birthday! How are things?
3. Happy birthday!
4. Hello Opalg, I am unable to post a reply to your response due some bugs in the website on the thread I started regarding complexification. I have asked Jameson to look into the issue. I will reply as soon as the issue is resolved.
5. HB, Opalg!
6. I actually was just going to send you a Happy Birthday wish...I hope you have a good one and I hope you enjoy your time in Gran Canaria too!
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#### May 29th, 2018

Ranks Showcase - 15 Ranks
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Name: MHB Challenges Solver Award (2017)
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Name: University POTW Award (2017)
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