Tab Content
• Today, 10:02
caffeinemachine replied to a thread Hi everyone! in Introductions
Hey Raisa! I am currently a PhD student in mathematics, but I was also a mechanical engineering undergrad before I switched to math. I would say that...
1 replies | 5 view(s)
• Yesterday, 18:23
Euge replied to a thread [SOLVED] How to prove continuity? in Analysis
Yes.
4 replies | 59 view(s)
• Yesterday, 18:19
Euge replied to a thread [SOLVED] How to prove continuity? in Analysis
It's a great idea, but for this argument to work, $f(c)$ needs to be positive. It's possible to avoid cases by setting $\epsilon = \frac12\lvert... 4 replies | 59 view(s) • Yesterday, 04:59 Joseph A. Gallian, in his book, "Contemporary Abstract Algebra" (Fifth Edition) defines an irreducible element in a domain as follows ... (he also... 0 replies | 34 view(s) • Yesterday, 04:23 Thanks for the help johng ... But i am still a bit puzzled ... I think we have to show that \{ \frac{k}{ 2^n} \ | \ k.n \in \mathbb{Z} \} is... 3 replies | 51 view(s) • Yesterday, 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 | 53 view(s) • February 16th, 2017, 23:12 I am reading Stephen Lovett's book, "Abstract Algebra: Structures and Applications" and am currently focused on Chapter 5 ... I need some help... 3 replies | 51 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 | 58 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 | 89 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 | 89 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 | 100 view(s) • February 12th, 2017, 22:13 Thanks for the help, Euge ... Appreciate your assistance ... Peter 2 replies | 61 view(s) • February 12th, 2017, 18:16 Euge replied to a thread I made it shorter in Analysis Hi sarrah, Why is $$\|P_1(t)\| \le \int_0^t e^{\|A\|(t - \tau)}\|B\|e^{\|A\|\tau}\,d\tau?$$ It appears you used a Minkowski type... 2 replies | 84 view(s) • February 12th, 2017, 18:03 Hi JGalway, To prove the result formally, I suggest using the principle of mathematical induction. 2 replies | 52 view(s) • February 12th, 2017, 17:57 Hi Peter, Yes, that's correct. 2 replies | 61 view(s) • February 12th, 2017, 17:28 Welcome, hksuraj! (Wave) What have you tried? Please show your thoughts on this problem, even if you only have the definitions. 1 replies | 59 view(s) • February 12th, 2017, 03:00 I have been thinking around the definition of a unit in a ring and trying to fully understand why the definition is the way it is ... ... Marlow... 2 replies | 61 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 | 105 view(s) • February 11th, 2017, 23:14 Yes, that's exactly the reason. 1 replies | 56 view(s) • February 11th, 2017, 10:06 Euge replied to a thread [SOLVED] Do the integrals converge? in Analysis I think you were missing my point. In your other post, the cosine is multiplied by a damping function, making the integral absolutely convergent.... 11 replies | 239 view(s) • February 11th, 2017, 08:06 Euge replied to a thread [SOLVED] Do the integrals converge? in Analysis Direct comparison requires the integrand to not change sign, right? The cosine changes sign over$[0,\infty)$, so direct comparison will not do with... 11 replies | 239 view(s) • February 10th, 2017, 23:00 Welcome, JGalway! (Wave) The expression you wrote for$E$should instead be$$\frac{\int_1^2 x\cdot \dfrac{x}{4}\, dx + \int_2^\infty x\cdot... 3 replies | 105 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 | 112 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 | 55 view(s)
More Activity

### 26 Visitor Messages

1. Hi Euge, I'm enjoying a quiet birthday, with just a few days to go before my wife and I go off for our annual holiday in the Canary Isles to escape some of the British winter.
2. Happy Birthday!!! Hope you had a great year and another one is to come! Thank you so much for all you do here.
3. Happy Birthday Euge!
4. Thanks, Euge!
5. Thank you, Euge! I hope you had a great weekend.
6. Thank you very much!!
7. Hi Euge!! On this special day.... I wish you happiness, health and so many good things in your life!! Happy Birthday, Euge!
8. Hey Euge, thanks. It's really an honor
9. Thank you, Euge!
10. Okay. I'll be waiting.
Showing Visitor Messages 1 to 10 of 26
Page 1 of 3 123 Last
Page 1 of 3 123 Last

Date of Birth
January 10
Country Flag:
United States

#### Statistics

Total Posts
1,336
Posts Per Day
1.37
Thanks Given
1,311
3,361
2.516
##### Visitor Messages
Total Messages
26
Most Recent Message
January 17th, 2017 12:59
##### General Information
Last Visit
Yesterday at 19:50
Last Post
Yesterday at 18:23
Join Date
June 20th, 2014
Referrals
1
Referred Members
eric509

### 9 Friends

1. #### caffeinemachineOffline

MHB Journeyman

2. #### Chris L T521Online

MHB Journeyman

MHB Master

4. #### MarkFLOnline

Pessimist Singularitarian

5. #### OlokOffline

MHB Craftsman

6. #### Pantaron EducatOffline

MHB Apprentice

MHB Master

8. #### Rido12Offline

MHB Journeyman

9. #### SudharakaOffline

MHB Master

Showing Friends 1 to 9 of 9
Page 1 of 4 123 ... Last

#### February 12th, 2017

Page 1 of 4 123 ... Last
Ranks Showcase - 6 Ranks
Icon Image Description

Name: MHB Advanced Algebra Award (2016)
 Issue time: January 9th, 2017 14:37 Issue reason:

Name: MHB Topology and Advanced Geometry Award (2015)
 Issue time: January 7th, 2016 11:09 Issue reason:

Name: MHB Analysis Award (2015)
 Issue time: January 7th, 2016 11:09 Issue reason: