Recent content by lxman
-
L
Undergrad A question about the speed of EM and mechanical waves
I have known for many years that the speed of sound (usually quoted ≈340 m/s) and the speed of light (usually quoted ≈3*10^8 m/s) are vastly different. Doing some reading, I would seem to conclude that part of the reason for this is the fact that sound is a mechanical wave, propagated through... -
L
Electrical stability of an atom
Alright then, let's see . . . eV is a unit of energy. Therefore would I be correct in concluding that the CO molecule has a quantity of energy closer to zero and therefore it would be more electrically stable?- lxman
- Post #3
- Forum: Introductory Physics Homework Help
-
L
Electrical stability of an atom
Homework Statement As shown in class the electric potential energy of a water molecule is -5.33 eV. Which molecule is more electrically stable, H2O or CO? Why? Homework Equations EPE=Kc*q1*q2/r12 The Attempt at a Solution The water molecule's EPE is -5.33 eV. The carbon...- lxman
- Thread
- Atom Electrical Stability
- Replies: 2
- Forum: Introductory Physics Homework Help
-
L
Determining the interval of convergence
Okay, [0,14] did the trick. Thanks for hanging in there with me. I have a couple of questions still left. First off, the inclusion of zero in the set. The way that I am seeing it, the coefficients themselves make up a series which is alternating and decreasing (actually beginning with term...- lxman
- Post #12
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Okay, I'm definitely not questioning you. Let me start from scratch with the problem definition directly from the homework and maybe I missed something or left something out. Represent the function f(x)=x^0.4 as a power series: \sum^{\infty}_{n=0}c_{n}(x-7)^{n} Find the following...- lxman
- Post #10
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Hmm, thanks much for the help, but I tried giving that to my professor and he says "not correct." I thought it would be (6,8], but just in case I was wrong, I tried [6,8], [6,8) and (6,8). He's not agreeing with any of them. I thought I understood things all the way, but I'm confused again.- lxman
- Post #8
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Nope, that should be: \left|\frac{1}{x-7}\right|<1 which tells me x>8 or x<6- lxman
- Post #6
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Okay, so looking at what I have to work with, I can calculate that: \frac{a_{n+1}\ (x-7)^{.4-n-1}}{a_{n}\ 7^{.4-n}}=\frac{.4-n}{n+1}\ (x-7) Now, the ratio test is looking at \lim_{n\rightarrow\infty} which would be x-7. Therefore, I need \left|x-7\right|<1\Rightarrow 6<x<8, and I still...- lxman
- Post #5
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Okay, that makes good sense. I have to define a center since depending on where I pick the center, the curve will be different and the interval of convergence will be different. So, my center is 7 in this case. What I understand from what you have written is that each successive numerator...- lxman
- Post #3
- Forum: Calculus and Beyond Homework Help
-
L
Determining the interval of convergence
Homework Statement f(x)=x^{0.4} Construct a power series to represent the function and determine the first few coefficients. Then determine the interval of convergence. The Attempt at a Solution Determining the first few coefficients is simple enough. Take the first few...- lxman
- Thread
- Convergence Interval
- Replies: 11
- Forum: Calculus and Beyond Homework Help
-
L
Estimating integral with Maclaurin series
Thank you all for your help.- lxman
- Post #11
- Forum: Calculus and Beyond Homework Help
-
L
Estimating integral with Maclaurin series
Okay, yep, missed that one completely. Integrating gives me: \frac{7x^{3}}{3}-\frac{49x^{7}}{6} Now, plugging in 0.77, I get -0.245385 which is much closer. Again, I presume the error is from only using two terms.- lxman
- Post #9
- Forum: Calculus and Beyond Homework Help
-
L
Estimating integral with Maclaurin series
SammyS, your idea sounds MUCH simpler, but you would have to explain the details of implementation to me. So, doing it the hard way - and yes, it gets a bit messy, so I won't post all the details. I end up with the first two non-zero terms being term 2, which evaluates to 14, and term 6, which...- lxman
- Post #7
- Forum: Calculus and Beyond Homework Help
-
L
Estimating integral with Maclaurin series
The original problem statement says to use the first two terms of the Maclaurin series. So when I am constructing the series, I just basically throw away any terms with zero values, and the non-zero terms then become my series. Is this correct?- lxman
- Post #4
- Forum: Calculus and Beyond Homework Help
-
L
Estimating integral with Maclaurin series
Homework Statement Assume that sin(x) equals its Maclaurin series for all x. Use the first two terms of the Maclaurin series for sin(7x^2) to approximate the integral: \int_{0}^{0.77}sin(7x^{2})\ dx The Attempt at a Solution If I understand correctly, a Maclaurin series is just a...- lxman
- Thread
- Integral Maclaurin Maclaurin series Series
- Replies: 11
- Forum: Calculus and Beyond Homework Help