• Yesterday, 11:04
MarkFL replied to a thread Hi everyone! in Introductions
Hello and welcome to MHB, Raisa! (Wave)
3 replies | 69 view(s)
• Yesterday, 03:13
Here is this week's POTW: ----- Find the exact value for the real root of the equation $x^3+3x-2=0$. ----- Remember to read the POTW...
0 replies | 51 view(s)
• Yesterday, 02:59
Congratulations to the following members for their correct solution::) 1. kaliprasad 2. lfdahl Honorable mention goes to cmath123, as he has his...
1 replies | 121 view(s)
• February 18th, 2017, 02:29
MarkFL replied to a thread 231.14.88 3d surface in Calculus
Multiplying through by $9+6x-8y$ and distributing the $26$, we obtain -x^2-y^2+z^2=156x-208y+234 -x^2-156x-y^2+208y+z^2=234 ...
3 replies | 54 view(s)
• February 16th, 2017, 09:40
Variation on Ifdahl's solution: Let $y = x + \frac1x$. Then $\bigl(\sqrt{y+1} + \sqrt y\bigr)\bigl(\sqrt{y+1} - \sqrt y\bigr) = y+1-y = 1$....
3 replies | 126 view(s)
• February 15th, 2017, 20:29
You have two points on the graph, so you can compute the slope as follows: m=\frac{\Delta y}{\Delta x}=\frac{y_2-y_1}{x_2-x_1} Then, you can...
2 replies | 59 view(s)
• February 14th, 2017, 23:47
Yes, the derivative of the function evaluated at the $x$-coordinate of the tangent point will give you the slope $m$ of the tangent line. :)
4 replies | 92 view(s)
• February 14th, 2017, 23:18
The first derivative of a function gives you the slope of the tangent line, not the tangent line itself. Thus,for some function $f(x)$, the tangent...
4 replies | 92 view(s)
• February 14th, 2017, 22:17
Let's try your substitution of: u=x+9\implies du=dx I=\int_9^{18}\frac{(u-9)^3}{u^2}\,du By the binomial theorem: ...
1 replies | 47 view(s)
• February 14th, 2017, 12:31
Just to follow up, we left off with: 8-\frac{15000}{x}=5 Arrange as: 3=\frac{15000}{x} Multiply through by \frac{x}{3}\ne0:
2 replies | 101 view(s)
• February 12th, 2017, 00:21
Yes, we use $\LaTeX$ powered by MathJax, which is what you'll find on most other math sites. The only difference is, unlike other sites, we provide...
3 replies | 106 view(s)
• February 10th, 2017, 11:34
Let's generalize the method I posted >>>here<<< to reflect a given point $(a,b)$ about the line $y=mx+k$, where ($m\ne0$). We will call the reflected...
3 replies | 113 view(s)
• February 10th, 2017, 10:27
MarkFL replied to a thread Line y = (x/2) + 3 in Pre-Calculus
Another way to show 3 points are collinear is to pick two distinct pairs from the 3 points, and show that the slope between both pairs is the same. :D
2 replies | 61 view(s)
• February 10th, 2017, 00:30
MarkFL replied to a thread Square root Convergence in Calculus
To extend the ladder for $\sqrt{k}$, you want: x_{n+1}=x_n+y_n y_{n+1}=x_{n+1}+(k-1)x_n
1 replies | 74 view(s)
• February 9th, 2017, 15:50
Now necessarily...for example if we multiply through by $k$, we get: k+1=k^2 And BOOM! we have question 1 of part B) done.
12 replies | 193 view(s)
• February 9th, 2017, 12:36
Here is this week's POTW: ----- Given that $\sqrt{x^3+1648}-\sqrt{4949-x^3}=75$ for $x\in\Bbb{N}$. Find $x$. ----- Remember to read the...
1 replies | 121 view(s)
• February 9th, 2017, 12:26
No one answered last week's problem.(Sadface) You can find the suggested solution as follows: Let...
1 replies | 139 view(s)
• February 9th, 2017, 03:49
We don't need to solve for $y$. We need only to have shown that: \frac{x}{y}=\frac{1+\sqrt{5}}{2} to satisfy part A) of the problem. For part...
12 replies | 193 view(s)
• February 9th, 2017, 02:15
That's not quite right: x=\frac{-(-y)\pm\sqrt{(-y)^2-4(1)(-y^2)}}{2(1)}=y\frac{1\pm \sqrt{5}}{2} Discarding the negative root, we obtain: ...
12 replies | 193 view(s)
• February 9th, 2017, 00:25
To solve for $x$ here, we let: a=1 b=-y c=-y^2
12 replies | 193 view(s)
• February 8th, 2017, 12:06
MarkFL replied to a thread Age Limit for Math Degree in Chat Room
Perhaps, but they will just have to deal with it as they will learn to do with many things they might find "a little odd" as they learn about the...
8 replies | 174 view(s)
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### 14 Visitor Messages

1. Thanks, you are doing a great job. I went through your Laplace transform tutorial. It is a good practice to try the Laplace transform of some new functions, and it is fun as well.
2. Er, DW, your .sig seem to be getting out of the separator of every post, so sometimes they are almost unreadable. Can you do something about it?
3. Wow, thanks for the new tutorial DW, it's just what I needed, a brief series of values of polygamma function and a closed formula in general. Thanks again! (To reply Visitor Messages, first click on "View Conversation" then reply to it)
4. Thanks for the tip, Balarka!! I've corrected it now... Was referencing a paper on arXiv.
5. DW, in your #3 post in "Generalized Log-Trig series related to the Hurwitz Zeta", shouldn't the Dirichlet characters be defined over $\mathbb{Z}/8\mathbb{Z}$ instead of what is given? $\mathbb{Z}/8$ is a weird beast...
6. DW, you should post those special value of Clausen function you have found out on the wiki article. It's nearly stub, I wonder why they didn't add that tag to it.
7. Not a bad idea, but it takes all the fun out of it...

It is pretty funny, mind... Folks join up, can get their heads around mind-bending equations, but fall foul of basic forum software. Oh dear!
8. Some have even humorously suggested we need to present a User's Manual to people when they join due to all the features we have here. Perhaps someday I will write such a manual...hehehe.
9. Thanks Mark! Just been toying around a bit and found out where to go. Cheers for your help!
10. Hey Gethin,

Here is a link to a topic explaining how to respond to visitor messages so that it gets posted on the recipient's wall:

http://mathhelpboards.com/questions-...hlight=message

Best Regards,

Mark.
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$\displaystyle \therefore\, \{ Life \} \cap \{ ridiculousness \} \ne \varnothing \quad Q.E.D.\, \Box$

$\displaystyle {\color{Blue}\mathscr{H}\mathfrak{e} }{\color{Fuchsia}\, = \, } {\color{RedViolet} \mathcal{MC}} ^{\color{OrangeRed}\mathsf{\, Scared !!}}$

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