Tab Content
• Yesterday, 06:59
Hello and welcome to MHB! (Wave) We ask that our users show their progress (work thus far or thoughts on how to begin) when posting questions....
1 replies | 33 view(s)
• Yesterday, 01:55
MarkFL replied to a thread Domain...2 in Pre-Calculus
No factor in the denominator can be zero, and nothing under a square root radical can be negative...so this leads to: t-1\ne0 0<t What do...
1 replies | 27 view(s)
• Yesterday, 01:47
I would write: y=\frac{2x}{x-1}=\frac{2x-2+2}{x-1}=\frac{2(x-1)+2}{x-1}=2+\frac{2}{x-1} We see this will have a horizontal asymptote at $y=2$,...
1 replies | 29 view(s)
• Yesterday, 01:31
Let's look at a definition: |u|=\begin{cases}u, & 0\le u \\ -u, & u<0 \\ \end{cases} Can you see that we must have: 0\le|u| ?
2 replies | 46 view(s)
• March 19th, 2018, 22:30
Yes, and as Wilmer was pointing out, you would likely want to use the binomial theorem. If you raise both sides to the 5th power, you get: ...
10 replies | 106 view(s)
• March 19th, 2018, 21:56
You're being asked to find an area, and in essence, you're doing so by adding up a bunch of vertical lines, the length of which are determined by the...
5 replies | 54 view(s)
• March 19th, 2018, 21:48
To follow up, we get: \d{x}{t}=\frac{\d{y}{t}\left(x-12y^2\right)}{9x^2-y} Plugging in the given values, we find: ...
4 replies | 52 view(s)
• March 19th, 2018, 21:07
That's already included in the "top curve minus the bottom curve." :)
5 replies | 54 view(s)
• March 19th, 2018, 09:46
Let's first look at the bounded region: And so the area is: A=\int_0^3 (-x^2+6x)-(x^2-2x)\,dx=2\int_0^3 -x^2+4x\,dx=2\left_0^3=2(18-9)=18 ...
5 replies | 54 view(s)
• March 19th, 2018, 08:38
To follow up, the washer method gives us: V=\pi\int_{x_1}^{x^2} R^2-r^2\,dx The volume of an arbitrary washer is: ...
3 replies | 82 view(s)
• March 19th, 2018, 02:24
I would first observe that $1+\sqrt{5}$ is a root of: x^2-2x-4=0 And so, the coefficients of the expansion: (1+\sqrt{5})^n Can be found...
10 replies | 106 view(s)
• March 19th, 2018, 02:02
2 replies | 36 view(s)
• March 19th, 2018, 02:00
2 replies | 42 view(s)
• March 18th, 2018, 23:25
1 replies | 105 view(s)
• March 18th, 2018, 23:03
We consider that both $x$ and $y$ are functions of time $t$, and so beginning with: 3x^3+4y^3=xy We apply on the left the power and chain...
4 replies | 52 view(s)
• March 18th, 2018, 22:27
Hello, and welcome to MHB! (Wave) We are given the curve: 3x^2+4y^3=xy In order to answer the given question, it will be helpful to...
4 replies | 52 view(s)
• March 18th, 2018, 07:58
MarkFL replied to a thread More integral substitution in Calculus
Is it possible it wants a decimal approximation there? Of course, then the issue is how many digits of accuracy? Gotta love these automated systems,...
12 replies | 104 view(s)
• March 18th, 2018, 07:44
MarkFL replied to a thread More integral substitution in Calculus
Okay, proceeding to part (b), I get (leaving off the constant of integration): \int e^{4x}\left(3+e^{4x}\right)^3\,dx=\frac{1}{4}\int...
12 replies | 104 view(s)
• March 18th, 2018, 06:57
MarkFL replied to a thread More integral substitution in Calculus
Let's step through the substitution a bit more slowly... \int e^{4x}\left(3+e^{4x}\right)^3\,dx=\int...
12 replies | 104 view(s)
• March 18th, 2018, 06:29
It is a related rate problem involving differential calculus (so that's why I moved it). Many places teach elementary calculus in high school. :)
6 replies | 58 view(s)
• March 18th, 2018, 06:26
MarkFL replied to a thread More integral substitution in Calculus
Where did the $u-3$ in the denominator of the integrand come from? It should just be: \frac{u^3}{4} If we pull the constant inside.
12 replies | 104 view(s)
• March 18th, 2018, 06:20
For a sphere of radius $r$, the volume is: V=\frac{4}{3}\pi r^3 Differentiating w.r.t time $t$, we have: \d{V}{t}=4\pi r^2\d{r}{t}\implies...
6 replies | 58 view(s)
• March 18th, 2018, 05:49
MarkFL replied to a thread More integral substitution in Calculus
Okay, if we make the suggested substitution, this means: u=3+e^{4x}\implies du=4e^{4x}\,dx And so for part (a) we may write: \int...
12 replies | 104 view(s)
• March 18th, 2018, 02:04
MarkFL replied to a thread More integral substitution in Calculus
I would try the substitution: u=2x Using this substitution, what do you get?
12 replies | 104 view(s)
• March 16th, 2018, 13:24
MarkFL replied to a thread Horizontal Asymptote in Pre-Calculus
Observe that: \frac{x^2+3}{x^2+5}=\frac{x^2+5-2}{x^2+5}=1-\frac{2}{x^2+5} As $x\to\pm\infty$, the rational term vanishes (gets smaller and...
5 replies | 42 view(s)
• March 16th, 2018, 07:37
Yes, that would be acceptable, except in the case where you are instructed to rationalize the denominator where you could write: ...
6 replies | 89 view(s)
More Activity

### 16 Visitor Messages

1. Hi Albert,

I was meant to reply to the PM but it seems to me your account here has exceeded your stored private messages quota and hence you cannot receive new message(s).

Anyway, I just wanted to thank you for reply and guess what, I just solved that challenge! Hurray! Haha...

Best,

anemone
2. Hi Albert,

I am aware that to editing our own post of less than 24 hours old (which I think is a good thing rather than keep adding responses by posting new follow-up posts to make mess of the look of one particular thread) is encouraged and not frowned upon, but I wanted to also let you know I have come to realize of your latest edit/update to my latest challenge only when I was about to reply to it. If by any chance I missed reading it, that would be unfair to you because your newest edited post deserves a credit, imho.

Thus in the future if you want to do a major edit to your previous post, I would recommend you to instead add another reply beneath your previous post, does that sound good to you, Albert?

Best wishes,

anemone
3. Hi Albert, congratulations on winning the MHB Challenges Award!
4. Hi Albert,

I wanted to say that I like your profile .sig, Little Prince was a story I read almost 2 years ago but it still touches my heart. It was the best story I ever have read in my life.

Best Regards,
Balarka
.
5. Hello, me again Albert!

Here is what our administrator Jameson has said regarding the issue:

"Ok, when that happens all he needs to do is reload the page. It should eventually render correctly. There's no need for more info. This happens for me periodically as well and I just reload the page. The only issue would be if after reloading many times he still couldn't see Latex."

So, when it happens again, try reloading the page, and if after several times the error still occurs, capture a screen shot and email the image to me.

Best Regards,

Mark.
6. Hello again Albert,

The staff here would really like to help, and it would be informative for use if you could get a screen shot of the error and email it to me, and I will forward it to the staff so we can see exactly what the error looks like at your end.

Best Regards,

Mark.
7. Hello Albert,

I have reported your problem to the staff here, and I can assure you they are a very knowledgeable and involved team of administrators whose primary goal is that our member's problems get addressed promptly.

Best Regards,

Mark
8. Hello Albert,

First I wanted to ask you if the issue you had yesterday was resolved...I waited for your email of the problem description but never got it. I want to help you get to the bottom of the problem if I can.

Second, I edited your latest post of the solution to the minimization problem. We try not to link to other math forums unless we are showing where a problem comes from if posted by someone else, to give credit to the OP. Since this problem is yours, you should post the solution at both places rather than at one, and then linking to that at the other.

Best Regards,

Mark.

1) http://www.mathhelpboards.com/f28/fi...equation-3193/ (Original title: please find n)

2) http://www.mathhelpboards.com/f28/bi...-squares-3198/ (Original title: mission impossible)
10. Hi again! You have asked in your thread >>here<< how to move a thread if you accidentally posted in a wrong sub-forum. The answer is you can't do that. However you can report the post by clicking on the little triangle (shown below) and writing down your request. I have moved your thread to the Challenge Questions and Puzzles sub-forum.

Showing Visitor Messages 1 to 10 of 16
Page 1 of 2 12 Last
Page 1 of 2 12 Last

#### Basic Information

Interests:
math,program,literature,music
Occupation:
math teacher
Country Flag:
Taiwan

#### Signature

One sees clearly only with the heart.Anything essential is invisible to the eyes
_______From The Little Prince By Antoine de Saint-Exupery

#### Statistics

Total Posts
1,225
Posts Per Day
0.65
Thanks Given
1,197
2,221
1.813
##### Visitor Messages
Total Messages
16
Most Recent Message
June 16th, 2014 23:06
##### General Information
Last Activity
February 21st, 2018 23:41
Last Visit
February 3rd, 2018 at 00:14
Last Post
September 25th, 2017 at 07:34
Join Date
January 25th, 2013
Referrer
anemone
Referrals
1
Referred Members
brat

### 9 Friends

1. #### anemoneOnline

Paris la ville de l'amour

2. #### jakncokeOffline

MHB Apprentice

3. #### MarkFLOffline

Pessimist Singularitarian

4. #### mathbalarkaOffline

MHB Journeyman

5. #### mathmaniacOffline

MHB Craftsman

6. #### Pantaron EducatOffline

MHB Apprentice

7. #### PranavOffline

MHB Craftsman

MHB Master

9. #### ZaidAlyafeyOffline

زيد اليافعي

Showing Friends 1 to 9 of 9