What is Test: Definition and 1000 Discussions

Hey all, The other day in O-Chem lab I tested trans-p-anisalacetophenone with the 2,4-dinitrophenylhydrazine test. I did not get the positive result that I expected. Is there any way someone could help me rationalize this? Would it have to do with the aromatic group in my compound? Did I...

I don't remember exactly how the question on my test was phrased but I believe it was phrased "Let A be an mxn matrix where m>n. Explain why in general there is not a solution to the equation Ax = b where b is a vector in Rm" This question was confusing to me because to me the meaning of...

There are 12 questions on an exam, and each student must answer 8 questions including at least 4 of the first 5 questions. How many different combinations of questions could a student choose to answer? So I got the number of ways a student can choose to answer the first 5 questions which is 6...

Homework Statement I'm designing a tyre test rig for a university project to measure camber, slip angle etc. An example of a test rig - http://www.ika.rwth-aachen.de/forschung/veroeffentlichung/1999/30.06.-02.07/im173g.gif Although my test rig will be for an RC car tyres, so not quite the...

Homework Statement Does the limit of (2y*x^2)/(4x^2-3y) exist as (x,y) -> (1,1)? If so what is the limit? The Attempt at a Solution So at first I thought I could just plug (1,1) into the equation and get two. My study buddy said that you have to make sure it approaches the same thing...

Hi, I will keep this short and sweet. I am drop testing an object of complicated geometry froma set height in 10 different orientations. Due to the complexity I decided to make a free falling rig where it slides (via roller bearings for example) when released. Simple freefall analysis...

Can the point to point test, (to determine the resistance between the main grounding system and all the major electrical frames, system neutral, etc) be made with an ordinary multimeter or does it need a special ground test tool? The NETA value of 0.5 ohm is widely accepted?

I see the open and closed circuit test on the transformer section I don't understand why we doing that(open and closed circuit test) can anyone explain and give some example?

Homework Statement determine whether the series (1-1/n^(1/3))^n converge or diverge Homework Equations all the testing procedure The Attempt at a Solution So I did the root test first, but the limit on the inside is 1. I then tried the ratio test but then when I tried taking the...

Homework Statement Use comparison test to see if the integral is convergent or divergent. Homework Equations integral [1,∞] (2+e^(-x))/x The Attempt at a Solution My books says that (1+e^(-x))/x is divergent and since my integral is bigger it is divergent also. TRUE OR...

Hi, I just took an IQ test, http://sifter.org/iqtest/ It relates the European IQ test to that of the Stanford-binet test. I just did it, but I was rather depressed and self-loathing, so maybe I could of done better... lol. I also was not aware of the time I was spending, perhaps better...

Over time I have realized that exams do not actually test intelligence (I can't define intelligence here but please bear with it). I'll take a specific example to explain this: - There are two people are I know, one of them always used to score more in math and the other less somehow. But the...

Homework Statement determine whether the Ʃ n4 / en2 is convergent or divergent? Homework Equations The Attempt at a Solution Using Root test: lim of n4/n / en as n approaches infinity But lim of n4/n as n approaches infinity = ∞0 So: Let N = lim of n4/n as n approaches...

I’m working with a Boolean parameter that has been proposed to identify good data and I want to test if it is effective on a data set where we know what is good (accurate) and bad (inaccurate results). The theory (sensu amplo!) behind the Boolean parameter, called “SC”, is that a value of “1”...

Homework Statement Ʃ cos(k*pi)/k from 1 to infinity. This is a test for convergence. and when is the proper time to use the alternating series test like using it on (-1)k(4k/8k) would result to divergence since lim of (4k/8k) is infinity and not 0 but the function is really convergent...

My textbook states that "For the integral test to apply, it is not necessary that f be always decreasing. What is important is that f be ultimately decreasing." I'm just curious what is meant by this statement. How do you define a function that is "ultimately decreasing"? It'd be great if you...

Is it possible to check the phase rotation sequence of a Medium Voltage Motor (Up to 6 kV) with one instrument? Does the shaft need to be moving while it is being tested? If instead of one, there are two motors electrically connected in parallel, with a common source feeder. will it be...

Homework Statement Test the following series for convergence or divergence. $$\sum_{n=1}^{\infty} \frac{1}{3^{\ln n}}$$ The Attempt at a Solution I've tried to compare this to geometric series ##3^n## but obviously the target term is larger overall than its geometric counterpart...

Homework Statement Preliminary test: If the terms of an infinite series do not tend to zero, the series diverges. In other words if ##\lim_{ n \to \infty}a_n \neq 0## then the series diverges. But if the limit is 0 we have to test further. Suppose a series a series satisfy this condition...

When performing a 2 hour pressure test on a waterline, the formula for calculating the allowable water loss over the 2 hours is given on the testing form. But, the form asks for the actual water loss. Of course, you know the pressure loss, but it asks for the water loss in gallons. This can...

If we have two sequences and the ratio of their limit is greater than zero, why does this mean that they either both converge or diverge? I don't understand why the test works. Also, what about lim[(1/x)/(1/x^2)] = lim x = ∞? The series of 1/x^2 converges but series of 1/x diverges...

Why we use v-notch in charpy impact test ?

The problem statement Recently I came across this problem and couldn't understand it. I know that in situation 1, the length of the specific place will be decreased; In situation 2, it will be increased. Can someone help me here? Thanks first!

This is a two-fold statistical thing I want to pursue and I'm unsure of which test(s) to use. Using data of gender and age at time of death from a large, old cemetery in town I want to compare two things: 1. Average life expectancy of citizens of our town compared to the national average 2...

Can someone please explain to me what if any is the benefit in using one lab quality 10 MHz OSC to run all your bench equipment ref OSC inputs? And, what about this GPS thing? Why use an expensive GPS synced 10 Mhz OSC source to drive your test bench? Thanks

Hi, I was wondering if someone could check to see if this problem is correct. For part "e" I originally was dividing put changed to multiplying is that correct? Thanks in advance for the help. A researcher was interested in the type of coffee that coffee drinkers prefer. A random sample of...

I quote a question from Yahoo! Answers I have given a link to the topic there so the OP can see my response.

Homework Statement Determine whether Ʃ(n from 1 to infinity) ln(n)/n^3 converges or diverges using the limit comparison test. Homework Equations I must use the limit comparison test to solve this problem-not allowed to use other tests. The Attempt at a Solution I know that the...

Under what conditions on the constants a and b does the second derivative test guarantee that the function g(x,y,z)=ax^2+2axz+by^2-2byz+z^2 has a local maximum at (0,0,0)? a local minimum at (0,0,0)? well, i used the Hessian matrix to compute the eigenvalues to set them above zero. but...

Hello! At work we have an UV aging test chamber that produces around 140 W.m^-2 UVA 15 W.m^-2 UVB and less then 1 W.m^-2 of UVC. The chamber is big, we have to go in and out to collect the items. Is it possible to have ozone formation or other harmful gases inside the chamber?

just wondering how people did and what you did to study and prepare. I plan on taking the physics GRE this september, however i haven't taken any quantum or classical (analytical) mechanics yet. Unfortunately, both sequences start this September also :( But i don't want to wait till next year...

1. Homework Statement [/b] Use the direct comparison test to show that the following are convergent: (a)\int_1^∞ \frac{cos x\,dx}{x^2} I don't know how to choose a smaller function that converges similar to the one above. The main problem is i don't know where to start. A simple...

Hi, friends! Since this is my first post, I want to present myself as an Italian who is trying to teach himself mathematics and natural sciences, while having a strictly humanities-centered school background, and I am tempted very much to enrol in a university scientific course. I read in the...

Homework Statement http://www.physics.ohio-state.edu/undergrad/greStuff/Problems_2009/Mechanics_4.pdf exercise 83 Homework Equations Conservation of energy?! The Attempt at a Solution Well what I think is that if there is no friction, whenever the initial velocity is >0, the...

Having some trouble with this. I think the answer to question 1 is 26% and question 2 is 2%. I'm not sure when to divide by 163 or 100?? practice test help: About 26% of orthopedic surgeries involves knee problems. The following table summarizes data collected from a sample of adults who have...

To all PFers who have played "Where's That Landmark?" over the years: it's all just an elaborate exercise to prepare for this game: http://geoguessr.com/ Lots of fun :biggrin:. I think I got to 12,000 once, I'm *certain* folks here can beat that.

hi there. I studied physics for years, even went as far as getting a PhD. but that was 13 years ago, since then rusty. Anyway something occurred to me and I wondered what you all would think about it. My question is, can anyone think of an experiment you could do to check if the "many...

Can anyone help me with this, please? It's about how you go about trying to decide if two distributions are consistent, statistically speaking; specifically, what statistical test, or tests, is (are) most appropriate to use. Here's the data: N(A) N(B) G/R/P 0043 0046 #101 0264 0235...

this is a problem in the topic of Concavity and the second Derivative Test The deflection D of a beam of length L is D=2x^4-5Lx^3+3L^2x^2, where x is the distance from one end of the beam. Find the value of x that yields the maximum deflection The answer to this is...

Homework Statement $$ \sum_{n=1} ^\infty\frac{1} {2^n} $$ Homework Equations The Attempt at a Solution I know just by looking at it that it converges no problem. You do the ratio test and you get something of the form \displaystyle\lim_{n\rightarrow \infty}...

i understand the reason for if the evaluated integral converges then the series also converges. However, just because the evaluated integral diverges, why does this automatically mean that the related series also diverges? the integral consists of every number of the +x axis when evaluating...

would someone please care to reword this proof for me? http://en.wikipedia.org/wiki/Limit_comparison_test it talks about ε, which is not even defined and then n0, which is again not defined, what the hell are all these variables... I'm sure someone here could do a better job organizing...

Is it possible that a future theory disproves quantum mechanics and relativity or one of them? People were convinced that Newtonian mechanics was correct and worked but relativity showed that it only works at low velocities etc...

I haven't seen a movie trivia thread in here. So I'll give this a go. The rules are: if you answer the current question correctly you get to ask the next one. Simple, huh? Only one question at a time, please. If no one correctly answers a current question within 24 hours of the posted...

Could you pass the voter literacy test Louisiana administered in the mid-60's? Ten minutes, 30 questions, 1 or more incorrect answers disqualifies you from voting. http://www.crmvet.org/info/la-littest.pdf Why, oh why, did I have to draw my triangle pointing to the right instead of up?!

RF Test Engineering -- Curious about the field Hi guys, I just graduated college and I have an offer for an RF Test Engineering position that sounds pretty amazing to me. The company is a telecommunications company that works mostly with gateway routers. I would be responsible for designing...

I just bought a eletric tool kit and this thing came with it: I think they are called test hooks but i just can't figure out what are they for.. I can't find nothing that connects to the top hole of that thing.

Homework Statement Ʃ(-1/2)^k from 0 to infinity. Homework Equations Ʃ(-1)^k*B_n from 0 to infinity where if the series converges 1. lim of B_n as n goes to infinity must = 0 2. B_n must be decreasing The Attempt at a Solution It doesn't look like there is a B_n in the original equation...

Use the comparison test to find out whether or not the following improper integral exist(converge)? integral(upper bound:infinity lower bound:2) 1/(1-x^2) dx Here's my solution for 3),but I think something went wrong For all x>=2 0<=-(2-2x)<=-(1-x^2) that means: 0<=-1/(1-x^2)<=-1/(2-2x)...

I am going to do the GRE subject test: physics, and I would like to know if any of you have some advises to study for this test, as well as books to use to prepare for this test. Also if you have already done the test it would be helpful to know about your experience.