Example Definition and 879 Threads

Can someone please show/explain to me the steps between the 2 circled formulas on the attached page #582 from Riley, Hobson, Bence - Mathematical Methods for Physics and Engineering 3rd edition. Thank you!

I considered ##X=\mathbb{R}^n## and quickly realized any linear functional like ##f=a_1x_1+\cdots a_nx_n## would attain a maximum on the boundary. I regret to say that my knowledge of topology is still very limited, and did a lot of experimenting with a pen and paper without fruitful results...

Hi My grandson who is dyslexic and who I need to help sometimes has the attached example paper for an exam which is iminent. The lecturer has gone is unavailable and he seeks to try fnd a source for te answers. Its a shot in the dark but I wonder if anyone can help please? Thanks Martyn

Hello dear experts. I want to run this input file flex_03.inp in fluka, but there is also a writect.f file belonging to this file.In another application, head.vxl, ascii_head are shown in the output files of this input file.What steps do I need to apply to the same files so that I can see this...

I just purchased this text. It is less comprehensive than the book by Adler, Bazin, Schiffers, and is written at an (mostly) undergraduate level. I have a problem with example 4.1 on page 35-6. What is meant by the down-arrow followed by the 1 in two equations 4.6-a, b? I am not sure...

Why is this post here in discussion? It is an example of how discussion proceeds in an area that is actually public health, ostensibly diet and health in the context of inflammation mediated disease processes caused by diet, specifically processed foods. We often have discussions that work like...

Ok, now I'm studying symmetrical components. Im using Stevenson's Power System Analysis book and example 11.9 asks for the zero sequence circuit of the example 6.1 in the same book. Here's the example and the solution: Here's example 6.1, so we can see what is the circuit: Here's the...

From the Lorentz transformation equations we know that $$t = \gamma(t^{'} - x^{'} v/c^2)$$ but for the Muon decay example where the setup is as follows : "Assume for simplicity that a certain muon is created at a height of 50 km, moves straight downward, has a speed v = .99998 c, decays in...

During a recent visit to the Modern Museum of Art in Fort Worth I came across this remarkable sculpture. It appears to be free standing (no strings attached). I assumed it is screwed into the floor and, for obvious reasons, I didn't poke it to see if it will tip over. My thinking is that the...

Wiki defines orthogonal functions here https://en.wikipedia.org/wiki/Orthogonal_functions Here's one example, but it's an example that is only true for a specific interval https://www.wolframalpha.com/input?i=integral+sin(x)cos(x)+from+0+to+pi So are these functions orthogonal because there...

Hello, I would like to confirm my answers to the following random variables question. Would anyone be willing to provide feedback and see if I'm on the right track? Thank you in advance. My attempt:

Hi, Back in the day, I remember my PC going from a x286 to a x386, to a x486, then pentium. It was fairly easy to compare the changes, it was easy to notice the clock speed that was increasing, from 33Mhz for the x386 to the 300Mhz for the pentium. In the recent years, we seem to be reaching...

Some BSM theories, often but not exclusively string theory inspired, have an extra time dimension, as well as extra spatial dimensions. I'm trying to make sense of what it even means to have more than one time dimension, ideally, with a concrete example that illustrates how the second time...

An example of how probabilities are calculated in poker hand. https://lh5.googleusercontent.com/pCynfBFNqfR00y8rEKWoXYkbSCGR310FpejMJ_iGWlwD7ttkCZjunp-TLKFMmU0A94CDsR4Bb-X8i6ai8RxiLLPdWlf1j9g6BZdjq1ppPZzp0JZOBjCVqwvKCK9XmGfg7Ks7VnN4IoWZIY3gqWvmKw Probability and Statistics with Applications: A...

[Mentor Note -- PF thread and MHB threads merged together below due to MHB forum merger with PF] I have to learn in context of lucene, but firstly, I want to learn the example indexing in general. Sth like this-: And I am not getting any google books and pdfs to learn about these topics. I...

Summary: Request for an example of minimum energy principle usage The minimum energy principle states that, for a system at constant entropy, volume and other extensive quantities, the internal energy is minimized at equilibrium. Can you give me an example in which, using this principle, is it...

I need a little guidance on how they got the last step to derive acceleration, I can follow up till there. Any help would be greatly appreciated as I find it hard to move on unless I have understood.

Disproof: Here is a counterexample: Let ## a=2, b=3, k=2, j=7 ## and ## n=5 ##. Then ## 2^{2}\equiv 3^{2}\pmod {5} ## and ## 2\equiv 7\pmod {5} ##. But note that ## 2^{7}\not\equiv 3^{7}\pmod {5} ##. Thus ## a^{j}\not\equiv b^{j}\pmod {n} ##. Therefore, ## a^{k}\equiv b^{k}\pmod {n} ## and ##...

Hi PF! Here looking at the first answer are two awesome examples of a vibrating membrane plotted from a top view. I can create the first example via fXYZ = {Cos[\[Theta]] Csc[\[Pi]/180] Sin[s Sin[\[Pi]/180]] - 0.001 Cos[\[Theta]] Cos[2 \[Theta]] Sin[ s Sin[\[Pi]/ 180]] (10.7721 (0...

The demo here doesn't specify how to download the file dowPortfolio.xlsx from the first line in the tutorial: T = readtable('dowPortfolio.xlsx'); Any help here (please tell me it's not just me)? Nevermind, evidently you literally can just copy that line into the command window and MATLAB...

Hi, I was attempting example 27.1 question from the book: 'Information Theory, Inference, and Learning Algorithms'. It is about the Laplace approximation. I was confused about part (b) of the question and wanted to check my method if possible. [EDIT]: The link to the book website (official) is...

NVM, these are all given: Find the altitude and azimuth of the Moon in Helsinki at midnight at the beginning of 1996. The right ascension is α = 2 h 55 min 7 s = 2.9186 h and declination δ = 14◦ 42 = 14.70◦, the sidereal time is Θ = 6 h 19 min 26 s = 6.3239 h and latitude φ = 60.16◦. It's...

Just a simple observation, hope it would be interesting. This example is very well known. It shows that if the conditions of the Cauchy-Kovalewskaya theorem are not satisfied then the solution is not obliged to exist. Consider an initial value problem $$u_t=u_{zz},\quad...

In the solution to the example problem, they wrote the following statement. “The least significant digit is the units digit, and so your weight is uncertain by about 1 pound. That is, your scale would read 119 lb for any weight between 118.5 and 119.5 lb.” I don’t understand why the scale...

I am studying IS but I am yet to find an example of IS. Is database IS? Is expert system IS? What is example of IS? And this question came to me while studying about this issue-: is security policy same as security methods? justify your argument with appropriate example of Information system...

1 example to represent the question in semantic net. https://lh4.googleusercontent.com/Gu5Cd7Xha3IDmtFfCHA7P_GCsQc9HyN9gt3a_M_2g1v_U3g8dHQyZkM537SZvQyhum0DyaaTGrmvVLBZWNq5z2tRFK_2fqg7y739u79WcDN31ipqtNzFH7CL95AlQgAMZOE7IPr9 Second question-: every student loves to party. Represent this in...

https://lh4.googleusercontent.com/FCqUErWAqlG8w0CskhcsLgpG91xyxzAkV_nD-bZAq8147-_RKesQDpglwqF5ylKZ0Q6VW88jX-KNuIpSXi9vhw5AiWmwiv_fMyyUo_WWZJG4uwWS0aB-3rGMA0h0PDo7ZpolexCe this is the question Here is a tutorial video but his steps are very confusing to me. I personally know bayes theorem and...

Really need this. Tried googling but not many. 1 or 2 are there. I want this algorithm solved by hand to some problem. IDK what kinds of problems exists. but one is knapsack problem. there is analytics vidya's tutorial but I want something else, more direct, more clear...Any resource you can...

Summary:: An elementary example calculation involving entropy in a textbook seems wrong I was reading an elementary introduction to entropy and the second law of thermodynamics. The book gave the example of a gas in a chamber suddenly allowed to expand into an additional portion of the...

I am from Nepal and instead of asking us code, these are types of questions that are asked in our country examination system. IDK what's their purpose. But some of them are badly hard as there are not many examples about it in textbook(In Nepal we can't get the textbook reference that the...

I am from Nepal and instead of asking us code, these are types of questions that are asked in our country examination system. IDK what's their purpose. But some of them are badly hard as there are not many examples about it in textbook(In Nepal we can't get the textbook reference that the...

Hello : i was looking into youtube the other day and watching some lectures , but start to wonder if there is a playlist for exercise solving on youtube for example for undergraduate math and physics ? do anyone knows of such channels or playlists ? Best Regards Hagop

This isn’t a HW problem per say, but it’s an example shown in my statics textbook that is used to try an explain that you need to add a couple moment to move a force to a point not on the line of action, and I’m just not seeing how the direction of the couple moment is correct. See the image...

any difference?

First of all I want to ask , do the LHC power klystrons work always in CW or are their frequency shifted to correct for timing of the bunches in the LHC tubes in case something isn't aligned or doesn't that ever happen? Also how do they drive the klystrons at LHC or other CW operation from an...

In Coleman's QFT lectures, I'm confused by equation 7.57. To give the background, Coleman is trying to calculate the scattering matrix (S matrix) for a situation in which the Hamiltonian is given by $$H=H_{0}+f\left(t,T,\Delta\right)H_{I}\left(t\right)$$ where ##H_{0}## is the free Hamiltonian...

I tried to think of a truly random phenomena thatis not related to quantum physics, and i can't. Let's take heads or tails as an example, if you had all of the data about the throwing of the coin you could tell on which side it will land. So does anyone know a random phenomena?

Hello everyone. I have been recently working in an optimization model in the presence of uncertainty. I have read https://www.researchgate.net/publication/310742108_Efficient_Simulation_of_Stationary_Multivariate_Gaussian_Random_Fields_with_Given_Cross-Covariance in which, a methodology for...

COVID-19 is thriving, while reported influenza infections are at record lows. As someone untrained in biology, I’m probably off the mark, but that sounds to me like an example of competitive exclusion. COVID-19 has a potentially longer incubation, it’s more contagious, people can be asymptotic...

I found this in wikipedia It only gives the definition of a Fredholm module. so i would like to find simple examples. what is this hermitian involutive F? thanks

I started reading about the “relational” interpretation of QM (RQM). I’m stuck on what appears to be a contradiction. The simplest way I can think to explain it is with a slight complication added to the Wigner’s friend experiment, adding an extra operation after the friend F measures the...

does this Beam, composed of three elements and 4 nodes(considering lateral deflections and slopes) has an 8x8 global stifness matrix and if so is the global matrix calculated the same way as a 6x6 stifness matrix for the same kind of beam but only with two elements and 3 nodes

Hello. I am reading Hibbeler's Mechanics of Materials (ninth edition). Example 7.5 computes shear flow at a segment where there are nails attached to different boards. He chooses a cut like the one shown here: And gets (by symmetry between C and C') the shear flow q computing the first moment...

I once read that if the Apollo 11 rocket had been misaligned by even half a degree on the launch pad that the lunar landing would not have happened. I would like to find this information again to use it as an example for my students in their life planning, i.e. if they make small mistakes now...

This is a question for experimentalists working in Condensed Matter Physics. What do you think is the most striking example of QFT vacuum state fluctuations affecting the results of an experiment? I have vague memory of reviewing some abstracts about quantum criticality in cuprate...

Hi PF! Do you know of any examples of the Ritz method which use Bessel functions as trial functions? I’ve seen examples with polynomials, Legendre polynomials, Fourier modes. However, all of these are orthogonal with weight 1. Bessel functions are different in this way. Any advice on an...

I have not studied the Fourier transform (FT) in great detail, but came across a problem in electrodynamics in which I assume it is needed. The problem goes as follows: Evaluate ##\chi (t)## for the model function...

This may be very simple but I'm having trouble working it out and the calculator isn't giveing me the result I need. Below is the example calculation: 1020000*0.5*[(1.10)1.5-1]= 78382 Here is the one I am having trouble working on 207559*0.5*[(1.10)1.5-1]= If someone could also show me how...

How to run a numerical simulation of Laplace equation if one of the boundary condition is like this: $$V(x,y) = 0 \text{ when } x \to \infty$$ I am trying to use Python to plot the solution of this Example 3.5. in Griffins EM

In the classic example of a person holding a spinning bike wheel, as they flip the wheel over, angular momentum is conserved by the person/chair spinning with 2x the angular momentum of the initial wheel. Not questioning that. However, I thought ang momentum is always conserved about a...