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karush
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Yesterday,
16:30
Theia
replied to a thread
Unsolved Challenge
Five, Phi and Pi in one integral
in
Challenge Questions and Puzzles
Taking your substitution u = \tan x, one obtains I = \frac{1}{2}\int _0^{\infty}u^{4/5}\ln \left( \frac{1+u^2}{u^2} \right) \mathrm d u. Now...
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3 replies  123 view(s)
April 22nd, 2018,
10:17
MarkFL
replied to a thread
Olinguito
in
Introductions
Hello, and welcome to MHB! (Wave)
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8 replies  102 view(s)
April 21st, 2018,
14:15
MarkFL
replied to a thread
Error 502, bad gateway
in
Questions, Comments, and Feedback
There was no inconvenience, except to you trying to post and to those trying to read the thread. It was bad coding on my part, done before I knew the...
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19 replies  514 view(s)
April 20th, 2018,
22:16
MarkFL
replied to a thread
BBCode For Username HTML Markup
in
vBulletin Products
Update  Version 1.3.1: Bug fix for usernames with special characters.
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2 replies  224 view(s)
April 20th, 2018,
19:16
MarkFL
replied to a thread
Error 502, bad gateway
in
Questions, Comments, and Feedback
I have added code to that external script so a single quote in a username won't throw an error, and I edited the post so that only the username is...
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19 replies  514 view(s)
April 20th, 2018,
12:00
MarkFL
started a thread
Problem Of The Week #310 Apr 20th, 2018
in
POTW for Secondary School/High School Students
Here is this week's POTW: A small bug is placed between two blocks of masses $m_1$ and $m_2$ ($m_1>m_2$) on a frictionless table. A horizontal...
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0 replies  38 view(s)
April 20th, 2018,
11:59
MarkFL
replied to a thread
Problem Of The Week #309 Apr 12th, 2018
in
POTW for Secondary School/High School Students
No one answered this week's problem, and my solution is as follows: A formula for power $P$ we can apply here is: P=\frac{1}{2}\mu\omega^2A^2v...
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1 replies  75 view(s)
April 20th, 2018,
03:34
Theia
replied to a thread
Unsolved Challenge
A tough Integral
in
Challenge Questions and Puzzles
Another observation: The integral can be written as I = \int _0 ^1 \frac{\ln ( \ln x)}{x^2 + x + 1} \mathrm{d}x  \frac{1}{2} \int _0 ^1...
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6 replies  181 view(s)
April 18th, 2018,
00:01
karush
replied to a thread
Compute \, S^k k=2,...,6
in
Linear and Abstract Algebra
yeah the op was supposed be a 5x5 I never tried mathamatica or the other exotic programs but sage looks good to me I have some more probs to...
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7 replies  119 view(s)
April 16th, 2018,
00:44
karush
started a thread
exercise treadmills
in
Chat Room
would it be possible to make exercise treadmillsa so they generate electricity rather than burn it. every time I walk by these fitness places I...
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1 replies  51 view(s)
April 16th, 2018,
00:29
karush
started a thread
Compute \, S^k k=2,...,6
in
Linear and Abstract Algebra
$\textsf{Let:}$ $$ S=\left$$ $Compute \, S^k k=2,...,6$ $\text{ok we are supposed to do this with SAGE}$ $\text{but not sure how $S^k$...
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7 replies  119 view(s)
April 15th, 2018,
20:01
MarkFL
replied to a thread
A Difficult Partial Sum
in
PreCalculus
Awesome work, as always Chris! (Yes) Using your post, where the base case and induction statement have been given, then the induction step would...
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6 replies  133 view(s)
April 15th, 2018,
12:02
MarkFL
replied to a thread
A Difficult Partial Sum
in
PreCalculus
Here are the choices: A.) \frac{1}{2} B.) \frac{1}{2}\frac{2^{2006}}{3^{2^{2006}}1} C.) \frac{1}{2}\frac{2^{2005}}{3^{2^{2005}}1} D.)...
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6 replies  133 view(s)
April 14th, 2018,
13:25
Theia
replied to a thread
Maximum Displacement in Projectile Motion
in
Challenge Questions and Puzzles
Thank you for your solution! ^^
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2 replies  62 view(s)
April 14th, 2018,
10:56
MarkFL
replied to a thread
A Difficult Partial Sum
in
PreCalculus
The actual sum he's given is: S=\sum_{k=0}^{2006}\left(\frac{2^k}{3^{2^k}+1}\right) And he's given several choices for the result. I was hoping...
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6 replies  133 view(s)
April 14th, 2018,
10:10
MarkFL
started a thread
A Difficult Partial Sum
in
PreCalculus
Hello MHB! (Wave) A young man in high school I know has been essentially tasked with finding the following partial sum: ...
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6 replies  133 view(s)
April 12th, 2018,
13:42
Theia
started a thread
Maximum Displacement in Projectile Motion
in
Challenge Questions and Puzzles
Let x = v_0\cos \alpha _0 t and y = y_0 + v_0 \sin \alpha _0 t  \tfrac{1}{2} gt^2, where v_0 is speed at time t = 0, \alpha _0 is the angle...
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2 replies  62 view(s)
April 12th, 2018,
11:47
MarkFL
replied to a thread
Hello from Pan
in
Introductions
Hello, and welcome to MHB panpan! (Wave)
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6 replies  94 view(s)
April 12th, 2018,
11:15
MarkFL
started a thread
Problem Of The Week #309 Apr 12th, 2018
in
POTW for Secondary School/High School Students
Hello, MHB Community! (Wave) anemone has asked me to stand in for her for a few weeks, so please be gentle. (Bigsmile) Here is this week's...
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1 replies  75 view(s)
April 12th, 2018,
11:11
MarkFL
replied to a thread
Problem Of The Week #308 Apr 6th, 2018
in
POTW for Secondary School/High School Students
Hello MHB Community! (Wave) I am going to stand in for anemone for a few weeks. Congratulations to the following for their correct submissions:...
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1 replies  133 view(s)
April 10th, 2018,
08:08
Theia
replied to a thread
Unsolved Challenge
Five, Phi and Pi in one integral
in
Challenge Questions and Puzzles
Is there an error in the result? I'm getting I = \int_{0}^{\pi\over 2}{\ln(\sin^2 x)\over \sin(2x)}\cdot \sqrt{\tan(x)}\mathrm dx = \frac{5...
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3 replies  123 view(s)
April 9th, 2018,
21:16
MarkFL
replied to a thread
Deduction
in
Discrete Mathematics, Set Theory, and Logic
Yes, that was a bad post. The OP stated an unfamiliarity with limits, so I "winged it." What I would actually do is: ...
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7 replies  108 view(s)
April 9th, 2018,
15:05
MarkFL
replied to a thread
Deduction
in
Discrete Mathematics, Set Theory, and Logic
I would write: ...
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7 replies  108 view(s)
April 9th, 2018,
14:47
MarkFL
replied to a thread
Deduction
in
Discrete Mathematics, Set Theory, and Logic
Take a look at what I posted for the $n$th sum of this same series, and see if you can't change in over to an infinite sum...
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7 replies  108 view(s)
April 9th, 2018,
14:34
MarkFL
replied to a thread
Geometric Series
in
Discrete Mathematics, Set Theory, and Logic
Okay, then the formula you first cited works in this case: S_{\infty}=\sum_{k=0}^{\infty}a_n=\frac{a}{1r} It is my understanding your sum is:...
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8 replies  109 view(s)
April 9th, 2018,
14:23
MarkFL
replied to a thread
Induction
in
Discrete Mathematics, Set Theory, and Logic
To properly use bracketing, you want: Sn = 1 + 1/(n+1) I would highly recommend learning to use $\LaTeX$ to make your expressions more...
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4 replies  66 view(s)
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karush
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November 24th, 2015
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April 22nd, 2018
01:08 
karush
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Re: Compute \, S^k k=2,...,6
by
I like Serena
Ok. I was curious now....
April 16th, 2018
03:54 
Krylov
clicked Likes for this post:
exercise treadmills
by
karush
would it be possible to...