Means Definition and 288 Threads

what exactly means (∂^2/∂x ∂y) ?? Not sure if I should post it here or in the homework section. feel free to move the topic if necessary. Due to some personal reasons I'm not attending college this semester. So I'm studying using the just books, which is kinda good but I have no one to...

Can someone explain to me what potential difference means? Lets say point A has a potential of 100 V and point B has a potential of 0 V. So V_AB would be 100 - 0 = ΔV But what exactly does that tell us? What does ΔV=100 do ?

Can anyone tell me the basics of Quasar? Note: Means that how it is created when there is only one dimension exists in a black hole and what is the reaction that occurs which emits so much light that it can be seen through millions of light year.

Here's my question: as soon as I learned Quantum Mechanics and Schrodinger equation, I saw a "similarity" with the equation one gets in classical mechanics for the evolution of a function in phase space. In QM one has: i\hbar\frac{d}{dt}\psi = \hat{H}\psi and this is a evolution...

I can't understand this problem, anyone can help me... Given a function y = 4x2, you are required to find the value of x that will result y = 2 by using the Least Mean Squares method. Use initial estimate x0 = 1 and learning rate η = 0.01. Write down the results of the first 10...

This is not homework problem, but I am using a problem from Elementary Modern Physics by Weidner and Sells as context for my question. It reads "A star is moving away from the Earth at 0.60c as measured in inertial system S, at rest with respect to the earth. At time t=0, when the star is 1.0...

Nano-----, what means? What is a nanoblade? And a nanospring? I am not an expert about nanotechnology but I would like to understand something more. Thanks in advance.

Suppose we have a function u=f(x,y,z) If \frac{\partial u}{\partial x} = 0 then u is independent of x and is u=f(y,z) only. Correct?

My course notes and textbook express this differently: To construct the confidence interval for diff. between means, Course notes (\bar{x1} - \bar{x2})\pmE Textbook (\bar{x1} - \bar{x2}) - E < \mu1 - \mu2 < (\bar{x1} - \bar{x2}) + E why the difference?

I'm currently trying to find out about radiative corrections to Feynman diagrams, where you have a particle traveling along (just represented by a line or whatever) then you can have it momentarily changing into a particle/antiparticle pair or whatever even if energy is not conserved - as long...

Hi Physics forums. I saw this question in a book, I'm not asking for the answer and this is not a homework, I just don't know how to figure out this: What can you say about a solution of the equation "y' = -(y^2)"just by looking at the differential equation? I checked at the book's answer...

Homework Statement http://img64.imageshack.us/img64/7782/circleb.jpg I'm supposed to find the slope equation of the tangent line to the circle at point A. A = (2, 7) The circle's formula is (x+1)2+(y+3)2 = 25 The center point of the circle is therefor (-1, 3) So the slope from the...

Not sure if he is just full of himself or if this actually means something... \ Any ideas?

General relativity states that all free falling bodies follow spacetime geodesics. A geodesic is a path of extremal proper time. My intuition tells me that extremal proper time is the maximum amount of real time. So does this mean that all objects will take the path of most time to get from...

Homework Statement Whenever LA talks about ℝn, do they mean just the n? Ex. Let's say I have two vectors \begin{bmatrix}1\\ 0\\ 0\end{bmatrix}\begin{bmatrix}0\\ 1\\ 0\end{bmatrix} Now it is tempting to say that the two vector is a basis for ℝ2. Now my professor tells me that it isn't a...

is it true that the voltage at a point means the quantity of charge at that point?if not then what is voltage? thanks

Hello everyone, Does anyone know what "handle" means such as below link: http://www.eng-tips.com/register.cfm Can anyone please tell me what should I fill within this field? Thank you very much in advance Huygen

As title... I am wondering is deltoid same as 'kite shape'? Thanks in advance...

Credits to Matt Might, whomever he is: http://matt.might.net/articles/phd-school-in-pictures/

I have nothing to add to the question that opens this post.

Hey guys, this is for an elementary statistics course. When given a problem, I am having trouble determining which is the data set (X) and which is the weight (W). For example: Using the weighted mean, find the average number of grams of fat per ounce of meat or fish that a person would...

I've done an experiment with human participants, n=40, so it's a large sample n>=30 from a large population. Now I'm trying to understand the statistical significance of my results and verify that I am interpreting things properly. This type of study is NOT my area of expertise. I'm basically...

i^i means WHAT?! My friend gave me the brain-teaser "i^i = what?", and with a little bit of coaching I finally discovered that i^i = e^(-pi/2) Which is cool, I suppose. But the more I think about it, the more I wonder: what the heck does it mean? For that matter, what does anything...

The raw data are lost, I have only final outputs (arithmetic means and standard deviations) for equally long measurement series. How I can compare results (calculate results) for the purpose to see significant statistic difference (significant difference, p<0.05)? Thank you in advance.

Does anybody of you know about this problem and how to compensate for it?

Hey folks! :smile: I am working through my text entitled Probability and Statistics for Engineers and Scientists by Walpole et al. I am getting a little stuck on their lackadaisical derivation of the standard deviation of the means. Perhaps I can get a little guidance here by talking it out...

Hi, I have been assigned to a new task in my job where I have to investigate on measuring the distance to an object by means of optical interferometry (Michelson interferometry). I have been looking for info on the subject but have not been really lucky. I have been able to obtain the...

What Product Log Means?? Hi, I have the following equation: B = (k*a*Exp[-t*(B/N)*T/beta] - N)/(a*Exp[-t*(B/N)*T/beta]) Using Mathematica, I tried to solve it for B. Mathematica returned the following solution: B = k-(N*beta*ProductLog[(E^((k*t*T)/(N*beta))*t*T)/(a*beta)])/(t*T)...

In flat spacetime what we say that something (energy, information, charge, whatever) is conserved we take some region of space at moment t1, check the amount of that something, then we count the amount of the same thing at t2. What is ‘at moment t1’? It means that we cut spacetime using 2...

http://www.nytimes.com/external/readwriteweb/2010/05/31/31readwriteweb-the-coming-data-explosion-13154.html An interesting book: http://research.microsoft.com/en-us/collaboration/fourthparadigm/ So basically, the two main paradigms used to be experiment and theory. Then in the 1950s came...

Hi! I'm reading up on confidence intervals for means. This is leaving my mind boggled. I caught the part where the interval = tc*(sample standard deviation/the square root of n). What's boggling my mind though is the variable tc. I see that t refers to a T distribution. But, I can't...

Homework Statement The problem is : For the functions from N*N --> N, determine if the following functions are surjective: f(a, b) = a + b f(a, b) = ab(b+1)/2 Homework Equations N is all natural numbers The Attempt at a Solution My problem is I know the definition of...

Racecar Winning Probability Index -- click to find out what it means So I just developed an equation that calculates how likely a racer is to win a particular race. It is not a probability ratio, which is why I'm calling it an index. RWPI(racer) = GRI(racer) / GRI(top competitors) where...

Can someone explain to me in the context of optoelectronic devices what rms linewidth means?? For example the rms linewidth of a particular laser is 0.1nm. What does that mean? and what implications does this have on a communications system using that laser? Thanks

sorry re posted in homework...

i can see the mean of "[]" in the first row,it is the anticommunicater between \gamma{\mu} and \gamma{\nu}, but what it mean in the second row and the third? thanks

restrocausality like the TI intepretation?

How is it that the lack of any info transferred between 2 entangled particles means that SR and Entanglement are not in conflict? I guess what I’m really asking is, well, it sounds to me like the lack of info is really just a lack of evidence that anything is transferred instantaneously. So if...

What is the best way to move hot air? Would it be blowing air across the heat source (ex: wood stove) or suck the air away from the heat source? I use a wood stove to heat my home which works perfectly, but it occasionally gets too hot in the living room (where the wood stove is). I want to...

i am now reading a prl paper the authors used numerical simulations to study a nonlinear system in some parameters, the authors state that system enters into chaos My numerical simulations are the same as that of the authors in the regular regime but in the chaos regime, my...

i am now reading a prl paper the authors used numerical simulations to study a nonlinear system in some parameters, the authors state that system enters into chaos My numerical simulations are the same as that of the authors but in the chaos regime, my simulations are quite different...

Homework Statement http://img264.imageshack.us/img264/7505/math.png Homework Equations AM = arithmetic mean = (a+b)/2 GM = geometric mean = sqrt(ab) The Attempt at a Solution I'm totally stuck on this, substituting does not help at all.

F=ma How do we define m and F? If their definition both come from this equation, then the equation doesn't really mean anything...We can also definite a F', and say F'=ma^2, and there isn't anything wrong... However, we have F=ma as something true, then F and m must be something true...

Homework Statement sample 1: size -10, mean -124, variance -1681 sample 2: size -5, mean -68, variance - 481 Assuming equal variance, independent and normality holds a)Is there any evidence that that the mean in population 2 is is less than the mean in population 1? Use alpha = 0.01...

i calculated the variance of a few measurements and i got the value of 3.65 i know the variance tells us the degree of dispersion from them ean value, and i came up with 3.65, what does this number say about the data?

Hi, 1: I just want to ask that what does SU(3) x SU(2) x U(1) means? and when a lagrangian is invariant under SU(3) x SU(2) x U(1) what does that mean? Does it mean that lagrangian L is invariant under SU(3) and then SU(2) and then U(1)? so if one wants to check SU(3) invariance of L...

Around 1998 we got the estimate of 71 from Wendy Freedman's Hubble Space Telescope team. That was called the "key project" of the HST program and was one of the main reasons for HST. So much depends on it that it is important to keep trying to improve the accuracy. That 71 has stood for 10...

what means "binding in equilibrium" ? hi there, im a german student and I've come across a phrase that is: (2) and (5) are binding in equilibrium, and (3) and (4) are slack. 2,3,4,5 are given equations, but can anyone explain that to me, so i can, without any knowloedge of the special...

Quick question, do bigger planet spin faster?

Dear experts, Does renormalization mean discarding corrections to a known constant? I mean, we assign a known value to the electron mass or charge, whatever, in the zeroth order of the perturbation theory, for example, in QED. In the next order we obtain a correction to this value (finite...