Test Definition and 1000 Threads

Homework Statement why the author said the series 9 converges by using alternating test ? for the alternating test , the first term the sequence must be in descending order , the it is said to be converges , right? however , in series 9 , 1 is >(-1/2) , but (-1/2) is not > (1/3) Homework...

I think I have a mold infestation in my apartment. Whenever I leave for a weekend and return my apartment has a harsh smell to it that irritates my nose and throat. I have not seen any obvious signs (such as discolored walls) so I would like to find a kit that will be able to test the...

Hi, so when doing a tensile test let's say on a threaded bar and a nut. The nut thread reaches failure and shoots off. How would you calculate that velocity and the actual force that it would hit say a wall 20cm away. just for information the failure point was at about 300kN

I'm building a web application that will have a lot of client-server action because (if everything goes as planned) there will be around 2000 users at once and a lot of database transactions happening with each user because I've set up event listeners that auto-save answers to questions on the...

In my country,we have an option of choosing our own subjects for high school.I have chosen physics,chemistry,biology and economics.So I don't get to study any high school math.For getting admission in college for a biology course,I have to take this SAT even though I hate math and aspire to do...

Where can I get multiple physics test papers by topic for undergraduates?

I am undergrad doing third year of my engineering. I looked into websites of many US universities for MS Applied math. Most of them require GRE math subject ( as far as I searched)test. The problem is am from engineering background and find it difficult to grasp seemingly simple concepts to math...

Hi All, Say we conduct a standard linear regression test of Y (dep) versus X (independent) Then there are tests to be made on whether there is a linear relationship between Y and X (with ##H_o ## being that m=0; m is the regression line slope versus ##H_A :m \neq 0 ##) Is there a similar test...

I conducted a uniaxial tension test for a variety of materials but wasn't able to gather much useful axial strain data due to the extensometer continually slipping. I have axial strain data for the linear elastic region of the stress strain curve and I also have the extension of the crossbar of...

Homework Statement ##P(z) = 1 - \frac{z}{2} + \frac{z^2}{4} - \frac{z^3}{8} + ... ## Determine if the series is convergent or divergent if ## |z| = 2 ##, where, ## z## is a complex number. Homework Equations ##1+r+r^2+r^3+...+r^{N-1}=\frac{1-r^N}{1-r}## The Attempt at a Solution Let, ##z = 2...

in optical stores.. you can see polarized sunglasses test card with image (like boat or trees). when you wear the polarized sunglasses, you can see the image that you won't see with normal eyes or normal glasses. i know polarized sunglasses work by filtering and seeing only the vertical light...

Hi everyone. Can someone please explain me how a two or three points test can be made, in the field of genetics? I've read of it in many books, but I'm looking for an explanation as clear as possible. Thanks in advance :)

Hi - my professor in functional analysis posted 4 prior years tests just 4 days before the test without solutions. I'd appreciate if anyone can help send solutions for the following with the following questions : 1. $\mu$ is a sigma additive measure over sigma algebra $\Sigma$. A $\in...

Will epsilon delta test fail if curve changed direction within the +/- delta of the limit point? Is there a scenario where no matter how small we pick delta to be, the frequency of the graph changing directions is always going to be a higher than delta's distance? In that scenario the limit...

$ \sum_{n}\frac{1}{n.{n}^{\frac{1}{n}}} $ Now $\frac{1}{n}$ diverges and $\ne 0$ , so by limit comparison test: $ \lim_{{n}\to{\infty}} \frac{n.{n}^{\frac{1}{n}}}{n} = \lim_{{n}\to{\infty}} {n}^{\frac{1}{n}} = \lim_{{n}\to{\infty}} {n}^0 = 1$ (I think the 2nd last step may be dubious?)...

$ \sum_{n} \ln\left({1+\frac{1}{n}}\right) $ $ \ln\left({1+\frac{1}{n}}\right) = \ln\left({1}\right) + \ln\left({\frac{1}{n}}\right) = 0 +\ln\left({{n}^{-1}}\right) = -\ln\left({n}\right)$ Now $\lim_{{n}\to{\infty}} -\ln\left({n}\right) \ne 0$, therefore the series diverges. (Also can you...

Hey, I am working on this problem over the root test but I am not sure if I am doing it right. I will attach my work to this thread and I really want someone to look over my work and see if I am doing it right. By the way I didn't finish the problem because I was not sure where to go from my...

Hey, I am working on Calculus III and Analysis, I really need help with this one problem. I am not even sure where to begin with this problem. I have attached my assignment to this thread and the problem I need help with is A. Thank you!

Hi All, I have been taking a class recently, and for some reason or another, professor has chosen not to return neither assigned papers nor exams , although some homeworks have been returned. I brought it up and got a non-responsive answer to the effect of "we cannot just do that". I have...

Homework Statement In a flame test lab, where different unknown substances are heated and the identity of the substance is determined by the color emitted, what can be some sources of error? Homework Equations n/a The Attempt at a Solution I need three sources of error, and so far I have...

Use the comparison test to see if $$\sum_{1}^{\infty}{\left[n\left(n+1\right)\right]}^{-\frac{1}{2}} $$converges? I tried $$n+1 \gt n, \therefore n(n+1) \gt n^2 , \therefore {\left[n(n+1)\right]}^{\frac{1}{2}} \gt n, \therefore {\left[n(n+1)\right]}^{-\frac{1}{2}} \lt \frac{1}{n}$$ - no...

Hi - just done the integral test on the Riemann zeta series, came out to $\frac{1}{p-1}$ I can clearly see it therefore converges for P > 1, is singular for p=1, but for p < 1 I can't see why it diverges? In the limit p < 1 just gets smaller? Would also like to check about p = 1, all I need...

Homework Statement The deterioration of many municipal pipeline networks across the county is a growing concern. An article stated that the fusion process increased the average tensile strength. Data on tensile strength (psi) of linen specimens when a certain fusion process was used and when...

Homework Statement In June 2010, chemical analyses were made of 85 water samples (each of unit volume) taken from various parts of a city lake, and the measurements of chlorine content were recorded. During the next two winters, the use of road salt was substantially reduced in the catchment...

Homework Statement The following are the number of sales which a sample of nine salespeople of industrial chemicals in California and a sample of six salespeople of industrial chemicals in Oregon made over a certain fixed period of time. California: 59, 68, 44, 71, 63, 46, 69, 54, 48 Oregon...

Homework Statement From extensive records it is known that the duration of treating a disease by a standard therapy has a mean of 15 days. It is claimed that a new therapy can reduce the treatment time. To test this claim, the new therapy is to be tried on 70 patients and their times to recovery...

Homework Statement An independent bank, concerned about its customer base, decided to conduct a survey of bank customers. Out of 505 customers who returned the survey form, 258 rated the overall bank services as excellent. (a) Test, at level α = .10, the null hypothesis that the proportion...

I've created a small liquid cooler and would like to test for it's cooling capacity. The only way I know of doing it is to circulate the coolant into a small reservoir with a heating element and apply power adding heat till the cooling unit is maxed out holding at a predetermined temperature...

Homework Statement use the comparison theorem to determine whether ∫ 0→1 (e^-x/√x) dx converges. Homework Equations I used ∫ 0 → 1 (1/√x) dx to compare with the integral above The Attempt at a Solution i found that ∫ 0 → 1 (1/√x) dx = 2 ( by substituting 0 for t and take the limit of the...

We consider a one photon experiment. If the photon really follow both path at the first beam splitter then only one detector will click, if on the other hand the photon would have to choose one path (classical particle) then both detector could click ?

This just showed up from a team led by Zeilinger, for those interested in loophole-free Bell tests: http://arxiv.org/abs/1511.03190 A significant-loophole-free test of Bell's theorem with entangled photons Marissa Giustina, Marijn A. M. Versteegh, Soeren Wengerowsky, Johannes Handsteiner...

I have scheduled a GRE test next week and in the ETS website it says that "Do not bring cell phones, smartphones (e.g., Android®, BlackBerry® or iPhone® devices), PDAs, digital watches, smartwatches and other electronic, recording, listening or photographic devices into the test center". Does it...

Homework Statement I have the proposal of making a math test thread in which instructors test student's knowledge in a specific topic. If you agree then post the same thread. For example: you have the topics that will be covered in your next exam such as permutations, combinations, bayes...

Hello everyone, I am trying to evaluate the spring constant of a coaxial polymer cylindrical fiber. This fiber has a stiff core and a more soft sheath. I know the geometry of the system and I know the Young's moduli of both components. I can find separate models for the core or for the sheath...

The diagram is a reproduction from instructions to perform an effective sensitivity test for a generic radio receiver. In our organization it's considered the proper way to do an effective sensitivity test for a receiver. My question is, what does the 6 db attenuator do in this case. It is...

Homework Statement Homework Equations The Attempt at a Solution I don't get how they got what's stated in the above picture. Where does 1/2 and n/(n + 1) come from? Can't you just show that an + 1 ≤ an?

Hey guys, this one is just for funnsies. So when dealing with an alternating series test, 3 requirements must be met, : Alternating u(sub n) ≥ u(sub n+1) for all n ≥ N, for some integer N u(sub n) → 0 as n → ∞. So I have been coming up with examples where of these are true, and one isnt. A...

Hi, Is it possible to determine the force (energy) behind a 300dia blank when under a pressure of 0.5bar and subsequently how far the force (energy) may move the blank which has a mass of 16kg? I know the volume and pressure of the air so can the stored internal energy be approximated by...

Hi friends , I am an electrical engineering student , interested in applying M.S in physics program in Europe . So i have started preparing for this , when i searched the web how to study for PGRE , most effective and common suggestion is go through the recommended books for each subject and...

How would you answer the following question? If ##(f\circ g)(x)=x##, then ##g## is the inverse function of ##f##. True/False? This is on a test that I gave and I now think it is a bad question, but I'm tired and I want to hear some other people's impressions. The wording of the question is...

Bee Hossenfelder called attention to an interesting paper in this post: A newly proposed table-top experiment might be able to demonstrate that gravity is quantized http://backreaction.blogspot.com/2015/10/a-newly-proposed-table-top-experiment.html Here's the paper...

Hi, I'm looking for the result of displacement controlled tensile test. I want to know about the x-axis component and y-axis component of the result, not the whole data. I read about some articles about these and they said displacement control is most common. I've searched a lot but all I found...

I'm thinking of giving gre test i don't know if i need only to give the subject test or general is must. i'm thinking of getting into physics Ph.D program so Physics GRE test. Please someone explain how am i supposed to give the test to be considered for a phd thanks

According to wikipedia AQFT needs test functions so that the fields are distributions smeared on these functions. I'd want to know what are these test functions. I read in Haag's book that they are fast decreasing functions defined on space time. They belong to the set S of Schwartz functions...

Homework Statement Not surprisingly there is an old forum post on this topic: https://www.physicsforums.com/threads/proving-force.46215/ However it doesn't contain the answer. Reposted: Two physics students are having a debate about the best way to define a force scale using rubber bands. Each...

1. Object 1 starts at 25 m and moves with a velocity of –5.5 m/s . Object 2 starts at 13 m and moves directly toward object 1. The two objects collide 0.65 s after starting. I need to find when they both collide and the velocity of Object 2 2. I don't know much but I know the displacement...

When interpreting the results of the two channel Bell test, I believe there were roughly 40 nanoseconds between when the particles were created and when they hit the polarized lens. It is believed that sometime during this time information passes between the entangled photons so that they match...

Given a sequence, how to check if it converges? Assume the sequence is monotonic but the formula that created the sequence is unknown. My first thought was if: seq(n+2) - seq(n+1) < seq(n+1) - seq(n) , is always true as n->infinity then it is convergent. Or in other words, if the difference...

Let's say I have some data and I want to test the hypothesis H_0 (only background) vs the hypothesis H_1 (bkg +signal). I did that using the ##p##-value and I got with a Z-score and two different approaches (taking all the data or the data within some mass window) the results: \it{p}_1 =0.105...

In slip test, we provide a constant 3 phase voltage across the stator of the machine. Then why does that voltage vary? Its like a variable inductor circuit due to different air gap length but basically if the voltage impressed is kept constant, why does the voltmeter show variation? Is it like...