Parameter Definition and 392 Threads

Hi I'm having some big problems with some data! I will try to keep this as simple as possible... I have a random variable that admits a probability distribution that I have a fit function for. With a large enough number of samples I can get good estimates of the fit function parameters via...

I'm in a second year physics course, and were studying Rutherford scattering. I'm not having any trouble with the physical or mathematical concepts, I'd just like a more precise definition of the phrase "impact parameter". I searched google, and my notes and textbook but couldn't really find...

Express the set of parametric equations x = E^t + e^-t and y = e^t - e^-t without using the parameter t. I really have no idea how to do this one. I tried substituting, and it just turned into a jumbled mess of nothing. Please help

Wald (p. 41) defines a geodesic as a curve whose tangent vector satisfies T^a\nabla_aT^b=0 . . . . . (3.3.1) Then he says that we could have defined it by requiring T^a\nabla_aT^b=\alpha T^b . . . . . (3.3.2) instead, where \alpha is "an arbitrary function on the curve", but we...

Homework Statement I'm trying to figure out the lattice parameter, c, of the HCP crystal structure. Here are a couple links showing the structure...

If my resonator is shorted at one end and has a partially transmitting grid at the other end is it correct to use S and T parameters to build a model of the device? I ask this as the first few sentences of the Wikipedia article on S-parameters states that a matched load should be placed at...

I am a little shaky on my probability, so bear with me if this is a dumb question... Anyway, these two random variables are given: X : Poisson (\lambda) \lambda : Exponential (\theta) And I simply need the marginal distribution of X and the conditional density for \lambda given a value for X...

If we have a fly in a room, its position respect to some frame of reference will change with time, so if we want to describe the fly's movement with a parametrized curve, it is easy to see the convenience of taking time as the parameter. I read that we can also take the length of the curve as...

I'm working on an experiment and trying to do some data analysis which seems to me should be fairly trivial, but I can't for the life of me figure it out. I want to know the value of some property A and to do so I'm measuring data points (x,y), which are related to the value I want by A =...

Homework Statement I've been measuring hubble's constant by calcultaing the redshift on a star and it's distance from Earth using a simple method of assuming galaxies have a standard size, then measuring their apparent size to gauge their distance away. To refine the model i have been asked...

Homework Statement Hello all, I have a parameter x of a matrix M = [21, 7 14, 7] the determinant of |(M - xI)| = 0 Homework Equations I is known as the identity matrix The Attempt at a Solution My solution seems to be a bit...

Homework Statement (D^2 + 2D + 1)y = ln(x)/(xe^x) Homework Equations D = d/dx The Attempt at a Solution First I find the roots of the left side of the equation, -1 of multiplicity 2. This leads to y(c) = Ae^(-x) + Bxe^(-x) Substituting A and B with a' and b' and dividing...

When an expression is derived using an "expansion in small parameters," what do they generally mean? I am not too familiar with this term, and the only thing I can think of are Taylor expansions. I have seen expressions that contain functions of these parameters, and after the expansion in...

How can I increment or decrement a parameter in LaTeX? For example, suppose I create an environment foo as follows: \newenvironment{foo}[2]{\begin{tabular}{*{#1}c*{#2}r}}{\end{tabular}} I can write \begin{foo}{4}{3} <tabular data in seven columns> \end{foo} But in my...

Hi, I'm trying to see why the following theorem is true. It concerns the derivative of the log of the determinant of a symmetric matrix. Here's the theorem as stated: For a symmetric matrix A: \frac{d}{dx} ln |A| = Tr[A^{-1} \frac{dA}{dx}] Here's what I have so far, I'm almost at the...

please help me to findout this problem i am putting this question second time bcoz i was unable to findout its category i am new here answer should be 2(pi)a

Homework Statement I'm trying to plot the trajectory of a photon near a schwarzschild black hole. I have the equation for the trajectory but I'm stumped by the impact parameter and cannot find out how to calculate it. Homework Equations \frac{d\phi}{dr} = \pm \frac{b}{r^{2}\sqrt{1 -...

Hey all I'm using a controller from MVP. The guide for the controller is located here: http://www.micromo.com/servlet/com.itmr.waw.servlet.FileViewer?sprachid=1&kid=42044&pid=531688&fid=531711&kdid=40929" . The controller's attached to a motor with a 2000 quadrature shaft encoder. I can get...

Homework Statement Find the range of the parameter d for which the intersection of the sphere x2+y2+z2=1 and the plane x+y+z=d is non-empty. Homework Equations Cartesian coordinates of a sphere: x=rcos\thetasin\phi y=rsin\thetasin\phi z=rcos\phi r=1 The Attempt at a Solution...

Homework Statement Alpha particles of kinetic energy 9.6MeV are incident on a silver foil of thickness 7.0 micro meters. For a certain value of the impact parameter, the alpha particles lose exactly half their incident kinetic energy when they reach their minimum separation from the...

Homework Statement Consider I = \int^{1}_{0} \frac{t-1}{ln t} (No, the problem does not contain a dt at the end of the integral, but I'll assume its a typo) Think of the t in t-1 as the a=1 limit of t^a. Let I(a) be the corresponding integral. Take the a derivative of both sides...

Homework Statement Plot \Delta w as a function of spectroscopic redshift for some given biases between spectroscopic and photometric redshifts. Homework Equations \Delta w = \frac{\partial D_{A}}{\partial z}\frac{\partial w}{\partial D_{A}} \Delta b D_{A} = \frac{c}{H_0} \cdot...

Hi, The current density due to field emission on a surface is described by the Fowler-Nordheim equation J = t(y)^{-2}a\phi^{-1}F^2\exp(-v(y)b\phi^{3/2}/F) where v(y)=1 - y^2+ (1/3)y^2ln y and y=cF^{1/2}\phi^{-1} F is the applied electric field above the surface. (See for example...

Hello people, I don't understand the relation between those concepts, I tried to read what's written in wikipedia about them but no use. Can someone please elaborate more about the relation between them in some intuitive manner? Thank you :)

Homework Statement Find the Arc Length Parameter along the curve from the point where t = 0 by evaluating the integral: s = ∫ |v(τ)| dτ from 0 to t Then find the length of the indicated portion of the curve. Homework Equations The vector I am using for this: r(t) = (etcos t)i + (etsin...

elimintate the parameter 1. x=lnt y=t^(1/2) e^x=t y=e^(x/2) 2. x=2t^3 y=1+4t-t^2 for slope = 1 dC/dt=(4-2t)/6t^2=(2-t)/3t^2=1 3t^2+t-2=0 t=-1 t=2/3 A(-2,-4) B(16/27,29/9)

How to convert a continuous inverse scale parameter into a physically relevant quantity: 1) What is a CISP, and why is called continuous and why inverse? 2) how do I deal with it: Example: On http://www.apec.umn.edu/faculty/gpederso/documents/4501/risk45DistFunc.pdf the error function is...

what was the value of the Hubble parameter when the universe was decelerating?

What are the odds that any particular big bang will result in the 20(?) fundamental parameters having the values that will allow life to form?

How would you find CI for some function of a parameter? the case I'm particularly interested in is an approximate CI for p^2 where p is the proportion in the binomial model. http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval

is there any need to introduce time as a parameter? is there any meaning of time, without any velocity? time is because of some change and that change can be measure by position only. so why is there an unnecessary extra parameter (time).is there any need to measure a rate of change with...

i have one problem on atomic radius. i read (http://en.wikipedia.org/wiki/Atomic_radius) the artical and try to understand it but i don't found any formula for it. The problem is: if the lattice parameter of alpha iron is 286 pm (Pico meter),what is its atomic radius? here we have only one...

Magnetic saturation seems to have a lot of influence on parameter behavior during load test on permanent split capacitor motors. Is there a method to integrate saturation in the equivalent circuit calculations . Is this possible when one uses the classical tests DC-test, Blocked rotor test, no...

I have a simple sounding question about QCD and its scale parameter \Lambda: The general consensus amongst field theorists is that QCD is not a well defined theory by its Lagrangian and the quantization procedure alone. One needs an additional parameter \Lambda, which sets the scale of...

Homework Statement http://mathbin.net/equations/8457_0.png My result does not seem like a "valid" equation. Is there any other approach I can take or anything that I can do to make it look prettier? Thanks.

I am reading some material on phase transition. In those, they use order parameter quite a lot, but what is order parameter? What's the physical significance of it? If I got the free energy , which involving order parameter m, how can I find the critical temperature?

How to solve the Free Parameter Problem in SUSY ?? In Standard Model, we have 19 free parameters: me Electron mass 511 keV mμ Muon mass 106 MeV mτ Tauon mass 1.78 GeV mu Up quark mass () 1.9 MeV md Down quark mass () 4.4 MeV ms Strange quark mass () 87 MeV mc Charm quark mass...

Could anybody tell me what is so called Quench Parameter ? And where is that parameter applys into? Thanks a lot! :smile:

Is parameter estimation in DSP concerned with things such as bit error rates, maximum likelihood detection etc ... ? If not, can someone point me in the right direction so I can find some learning material. thanks

Homework Statement Construct a One-Parameter Family of implicit linear two step methods of greatest possible order. Homework Equations \alpha1 yn+1 + \alpha0 yn = h (\beta0 Fn + \beta1 fn+1) I've attempted a solution, but my question isn't involving it. I'm having a major brainfart...

basically i need to convert the following parametric equation: x=a cos (T) + b cos (T/2) y=a sin (T) + b sin (T/2); where a and b are coefficients to cartesian form: y = f(x) i need it in that form so i can do calculus analysis for an improved engine design i hope to develop. thanks...

f(x) is a continues function on (-infinity,+infinity) for which f(x+y)=f(x)+f(y) prove that there is parameter a for which f(x)=ax for every real x i was given a hint to solve it for x in Q there is no much thing i can do here for which i can use theorems the only thing i am given...

Homework Statement Find the general solution using the method of variation of parameters of: y''-6y'+9y=(x^-3)(e^3x) I found the roots of the corresponding homogeneous equation to be lamba = 3. So there are repeated roots. My question is, how do I solve a variation of parameter...

Homework Statement Let X\sim Poi(\lambda) and assume \lambda\sim Uni(0,5) Q: Find \mathbb{P}\{X \geq 3\}Homework Equations For a Poisson r.v. with parameter lambda, \mathbb{P}\{X = k\}=\frac{\lambda^{k}e^{-\lambda}}{k!} and the probability that lambda is in the interval (0,5) is 1/5 and 0...

i tried to solve it but i didnt get any parameter value ?? http://img403.imageshack.us/img403/5395/25739192yz6.th.gif

Hello, I am using COMSOL (RF modul) for some time now to calculate the eigenvalues (modes) of optical fibers. So far I changed all the params from hand in the software. But it is getting anoying to change a parameter (the wavelength) and to recalculate if one wants to calculate for many...

hi there! I have the following sum: \displaystyle{\sum_{n=1}^\infty}(-1)^n\frac{(2z)^n}{(2n)!} and I want to let it run from n=0 to infty it´s somehow obvious that: \displaystyle{\sum_{n=0}^\infty}(-1)^n\frac{(2z)^n}{(2n)!} -...

Hi, Is it true that the standard gravitational parameter of an object (G*M) is more accurately known than the the gravitational constant (G)? If so, why? Any references would be much appreciated. Thanks, San

Homework Statement My problem has to do with impact parameter of two billiard balls. I don't want my problem solved persay, I just want to understand the problem, as I have a few things I am unclear about. If impact parameter is what "would've been the distance of the closet approach of the...

It is the question ,I had posted some threads but i couldn't clarify my idea but now i came with the question . Can time be T=f(p) ?