Test Definition and 1000 Threads

A quiz has 4 questions with 3 choices for each answer. If you guess every answer, in how many different ways can you complete this test?__________ How many students must take this test to guarantee that at least 3 identical answer sheets are submitted?__________ I know how that the answer to...

Homework Statement See attached image. (it should say "ratio" not "ration") Homework Equations Ratio series test: An+1/An The Attempt at a Solution I have worked this problem over and over and continue to get the same solution. Some guy worked it on the board a couple of days ago and got...

I am in a zero mass spaceship at rest in my chosen frame of reference. A cylinder with a diameter equal to the sun and of infinite length is passing at 8 minutes light travel distance and has a velocity of 99% x the speed of light traveling with the length of the cylinder with respect to my...

Hello, I'm in need of major help on some equations.. I have an exam coming up for finals and I'm horrid at algebra in general. I'm in intermediate algebra for the second time. Soo.. yeah, help would be greatly appreciated. Thank you! (Please explain step by step.) 1. Rationalize the...

Homework Statement f(x,y) = x^{2}+y^{2}-2x, D is a closed triangular region with vertices (2,0) (0,2) and (0,-2). Find the absolute max and min of f on D. Homework Equations Hessian matrix. The Attempt at a Solution Taking the second partials I end up with the system of equations...

Homework Statement Use the comparison test to show that the series converges, and find the value it converge to by using partial fractions. ∑ n=1 -> ∞: \frac{2}{n^2 + 5n + 6} Homework Equations The Attempt at a Solution The series can be written as 2 * ∑ n=1 -> ∞...

Hi there! Im new to this forum so pardon me if this is the wrong place to post my question. Basically, I have an idea with regards to doing some modification to phone screens. However, there is no such technology (yet) for this and I have zero knowledge and background pertaining to...

Homework Statement I've found that the typical way for using ratio test is to find the limit of an+1/an However, my tutor said that radius of convergence can be found by finding the limit of an/an+1 and the x term is excluded. For example:Finding the interval of convergence of n!xn/nn my...

We manufacture crank case heaters and they are designed with an 800V 1A STD Recovery diode. We do not Hi-pot the heater with the diode in it we only test to make sure we have an ohm reading in one direction and an OL in the other. However, our customer installs our heater into a system and...

Homework Statement Evaluate ## ∑^∞_{n=1} \frac {2}{n(n+2)} ## 2. The attempt at a solution I've solved this question simply enough by evaluating it as a telescoping series and found the answer as 3/2. Now, when applying the integral test, it only works when dealing with positive, decreasing...

I'm studying using the popular Lindenberg book. It suggest I have to memorize about 30 elements and their respective oxidation numbers. However, the book was written before they revamped the exam. Anyone know if I still have to memorize this?

I have done a test on a 4 piston test engine which is expected to exhibit torsional resonance at 800RPM and a vertical translational resonance at 1200RPM. The data we gathered from the test bed machine was as follows: Theta | Signal 0 | -5 60 | -1 120 | 7 180...

Hello, it is well-known that the Chi-square test between an observed distribution O and an expected distribution E can be interpreted as a test based on (twice) the second order Taylor approximation of the Kullback-Leibler divergence, i.e.: 2\,\mathcal{D}_{KL}(O \| E) \approx \sum_i...

This is a problem from My book which I have hard understanding what they are asking for, I am pretty confused on the question would like to have help! Second derivate test works as follows: If f (c) = 0 and f'' (c)> 0 Then c is a local min point for function f (a) Show that c need not be a...

Suppose: $$\int^{\infty}_1 \frac{x}{x^2 + 1} \, dx$$ I can't do this can I? Let $$u = x^2 + 1$$ so $$du = 2x \, dx$$ $$\therefore \frac{du}{2} = x \, dx$$ ?

I was taking a test yesterday and this question came up, it could possibly be the only one I missed on the test. I roughly sketched and described the problem to the best of my memory, but I guarantee that all of the essential information is there. I have attached the problem to this question...

Homework Statement "Is there sufficient evidence to support the claim that the mean content of all such containers is at least 3 litres? Homework Equations The Attempt at a Solution I'm not sure what H0 and H1 will be H0: The mean content is not at least 3L H1: The...

Hello, I have a 16x16 contingency table, and I would like to perform a test in order to reject the hypothesis of independence between the variable X (columns) and the other variable Y (rows). Unfortunately many cells in the table contain zeros. The zeros are due to the fact that the sample...

I work at a company that manufactures TPU screen filters for the mining industry. I've got a test to do to inspect whether the qaulity of the TPU is affected by time in the heated barrel of the injection moulding machine. The TPU material sits in the barrel due to tea and lunch breaks (15 - 30...

I've never done this before, and undertook it for the first time today, guided by books, google, and YouTube. My truck's a 4 cylinder. I did the first test after driving it for a while to warm it up. I got 150-150-146-140 psi for the four respective cylinders 1-2-3-4. The instruction I was...

Suppose ##f^{\prime\prime}## is continuous on an open interval that contains x = c 1. If ##f^{\prime}(c)=0## and ##f^{\prime\prime}(c)<0##, then ##f## has local maximum at x = c. 2. If ##f^{\prime}(c)=0## and ##f^{\prime\prime}(c)>0##, then ##f## has local minimum at x = c. 3. If...

I played around in another thread with mathematically determining where a car should be time wise on 1/4 mile run. I had a chance to drive this car myself giving me more information than you normally have on a car you have yet to buy. As I thought more deeply about my calculations, I became...

The graph of a differentiable function y=f(x) is 1. concave up on an interval I if f' is increasing on I. 2. concave down on an interval I if f' is decreasing on I. Let y=f(x) is twice differentiable on an interval I 1. If f'' > 0 on I, the graph of f over I is concave up. 2. If f'' <...

Homework Statement U= { (x1, x2, x3, x4) | x1 x3 ≥ -5 } The Attempt at a Solution Let x = (1,2,3,4) and y = (1,2,3,4) x+ y = (2,4,6,8) x1x3 = 2x6 = 12 12 >-5 so closure by addition is fulfilled. I've been hearing contradicting information-some state that any 1 test of...

I was completing a chapter on momentum in my physics textbook. I took the test, in which I encountered the following question: Would a cat without a tail be able to right itself while falling so that it always landed on its feet? Earlier in the chapter the author explained that cats were...

Homework Statement Test to see if \sum_{n=1}^{\infty}{ i^n/n } converges.Homework Equations See above. The Attempt at a Solution If I separate this series into real/imag. parts both series diverges by the integral test. However, according to Wolfram Alpha, the series converges to...

This might seem like a rudimentary question but when trying to prove divergence (or even convergence) of an infinite series does the series always have to start at n = 1? For example would doing a test for \sum^{∞}_{n=1}\frac{1}{n} be any different from \sum^{∞}_{n=0}\frac{1}{n}

Homework Statement A 50 KVA,6360 V/230 V transformer is tested on open and short-circuit to obtain its efficiency,the results being as follows: O.C.: Primary Voltage-6360 V, Primary Current-1 A, Power Input - 2 kW S.C: Voltage across primary winding-180 V Current in secondary...

Homework Statement ∞n=1∑(-1)n\stackrel{10n}{(n+1)!} Homework Equations The Attempt at a Solution I already found that the limit does equal zero by using the ratio test on bn. What I'm having trouble with is determining if it decreases or not. I know you can't take the derivative...

Hi all I am comparing the performance of two models and have calculated the coefficient of determination R squared for each. I would like however to test the significance of this value. The F test however requires that the number of degrees of freedom for each model. The trouble is one...

I am not sure if this is the right sub-forum to post this question in or not, if not I appologize for posting in the wrong place - it looked like the most likely forum to be the correct one. In a sci-fi book I was reading, the author talked about an 'artificial symbiote' being created by 15...

Hi y'alllll! Need some guidance on a little issue, As you very well know, european standards (ecss) exist for space systems but they are generally outlined for launch vehicles. Do specific standards exist for payload fairings? For example a test sequence is outlined for general space...

1. A 30kg box is placed on a 15° slope and a person pushes on the box up the slope to keep it from sliding. If the coefficient of static friction is 0.15, what is the minimum force that the person must exert to keep the box in place? Answer Choices: A. 273N B. 241N C. 33.5 N D. 64.7 N E. 294 N...

For when there is a negative test charge: The work done to get from infinity to r would be negative, corresponding to a decrease in potential energy so since dr must be a path element and therefore in the negative direction (towards the source of the E field) does that mean the...

When considering tempered distributions, I am only aware of the definition of test functions of a real variable. However, is it okay to use test functions of a complex variable z that are analytic in a strip that includes the real axis? (of course they still must fall off fast enough as the...

Homework Statement Ok, so in a lab I was preforming Izod impact tests on notched polymer specimens. To complete my calculations I need to determine the correct cross-sectional area to use (Which is baffling me as the simple things usually do) The sample was loaded with the notch facing...

I need help deciding which AP Physics test to take. Currently, I am a junior taking AP Physics BC, which my teacher claims is between AP Physics B and C. It looks like all we will learn this year is mechanics, maybe touch on electricity. Our teacher isn’t giving us any AP test questions or...

Homework Statement Determine if the following series is divergent or convergent: ## ∑_1^∞ \frac {(2)(4)(6)...(2n)}{n!} ## 2. The attempt at a solution I understand this can be simplified to: ## ∑_1^∞ \frac {(2^n)(n!)}{n!} ## This can easily be seen to be divergent. But when I...

Null results so far for the elusive gravitational search, but were they expected to be found at this range? arXiv:1402.4974 (cross-list from gr-qc) [pdf, ps, other] Implementation of an F-statistic all-sky search for continuous gravitational waves in Virgo VSR1 data J. Aasi, B. P. Abbott, R...

How does one derive the second derivative test for three variables? It's clear that D(a,b) = fxx * fyy - (fxy)^2 AND fxx(a,b) Tells us almost all we need to know about local maxima and local minima for a function of 2 variables x and y, but how do I make sense of the second directional...

Looking for ideas... At my work, we test a number of products that come with flying leads, using this kind of connector: http://www.digikey.com/product-detail/en/33-1404/GC400-ND/258507 I'm looking for something a little more durable. These things have plastic clips to hold the leads in the...

In one case I get the results as a significant difference in the other with the same dana, the difference is not significant. Data sample A B I 5 8 II 4 28 http://imageshack.com/a/img542/467/o61k.jpg Same data and got significant difference...

Homework Statement If z is east and y is north then x is? A. West B. East C. North D. South E. Down Homework Equations I have trued getting the proper orientation but the direction I would have obtained is not an option 'up' a comment would be appreciated The Attempt at a Solution

25 questions, multiple choice, 5 choices per question. Correct = 6 points blank = 1.5 points wrong = 0 points. I should know how to do this, but have a cold and simply can't wrap my head around it… Danke Schoen!

Hello guys, I was searching for what voltage does IEC standard call for Di electric test that should be done to low voltage panels? is it 2.5 KV for 1 minutes? If yes how how low voltage cable rated 600/1000 V can withstand 2.5KV without insulation failure?

Hello, I was trying to interpret the formula of Pearson's Chi-squared test: \chi^2 = \sum_{i=1}^{n} \frac{(O_i - E_i)^2}{E_i} I thought that if we assume that each O_i is an observation of the random variable X_i, then the above formula essentially considers the sum-of-squares of n...

Homework Statement Use $$\sum\limits_{n=1}^∞ \frac{1}{n^2}$$ to prove by the comparison test that $$\sum\limits_{n=1}^∞ \frac{n+1}{n^3} $$ converges.Homework Equations $$\sum\limits_{n=1}^∞ \frac{n+1}{n^3} \equiv \sum\limits_{n=1}^∞ \frac{1}{n^2} + \sum\limits_{n=1}^∞ \frac{1}{n^3} $$ The...

Homework Statement Hester suspected that a die was biased in favour of a four occurring. She decided to carry out a hypothesis test. When she threw the die 15 times, she obtained a four on 6 occasions. Carry out the test, at the 5% level, stating your conclusion clearly. Homework...

Homework Statement $$\sum\limits_{n=1}^∞ \frac{1}{n√(n)} $$ Since $$ \frac{1}{n√(n)} \equiv \frac{1}{x^{3/2}} $$ this is a convergent p-series. But, when I attempt to prove this by the limit comparison test with known convergent series such as $$\sum\limits_{n=1}^∞ \frac{1}{n^2}$$ ex...

Hey, not too sure about what function i would compare this integral from 1 to infinity of (3x^3 -2)/(x^6 +2) dx. I also have to show that it converges. Thanks!