Parameter Definition and 352 Threads

Let D be the following circle with the radius a. http://img580.imageshack.us/img580/6402/97833345.jpg Find the parameter a for which f(a) gets its minimal value. http://img844.imageshack.us/img844/2993/91289562.png

Hi folks, I have a differential equation which looks like sin(f) + \frac{1}{Q}\frac{d(f)}{dt} + \frac{d^2(f)}{d t^2} = g(t) Now for Q << 1 this should, according to our lecture, simplify to sin(f) + \frac{1}{Q}\frac{d(f)}{dt}}{d t^2} = g(t) Why that? I mean, obviously for Q<<1, 1/Q >> 1...

I have trouble figuring out this problem. If someone can help me out that would be appreciated. Suppose we have x^3 -x + C let r denote the largest root of the equation. What's a mathematical way of relating r and C? (quantitative). Also what's dr/dc Thanks in advance.

Homework Statement Are the following models linear in parameters? If not, is there any way to make them linear-in-parameter mode?(The picture is in the attached) Homework Equations The Attempt at a Solution I tried to use dy/dx to show that they are not linear as the dy/dx is not constant...

Homework Statement So I'm given x(t)=4cos(t) and y(t)=sin(t). In a 4 part question, I 1st need to eliminate the parameter to get the equivalent rectangular equation, 2nd I need to find the slope of the tangent to the curve C-y(x) at t=1, 3rd find the times the tangent to the graph is...

I know that a Schwarzschild metric cannot have negative mass parameter. But what about regions? It is possible to have negative mass parameter between two spherical shells? If not, what is the argument?

Homework Statement A system has a two component order parameter: [phi1, phi2]. The mean-field Landau free energy is E(\phi_1,\phi_2) = E0+at(\phi_1^2+\phi_2^2)+b(\phi_1^2+\phi_2^2)^2+c(\phi_1^4+\phi_2^4) where t, a, and b are positive constants. Represent the order paramter as a vector on...

I would like to generate a plot displaying the parameter t on the x axis, varying from 0 to 0.95 and the corresponding values of e1. My code below does what I want (I think) but is plotting all the different points on different graphs (all 950 of them!). How can I get it to plot on the same...

Sorry for the wordiness of the thread title. Basically I'm wondering, if you have two implicit functions, F(x,y)=0 and G(x,y)=0 (typically rational functions with numerator and denominator very high degree polynomials), both dependent upon the same K (in my case > 34) dimensional set of...

Hi, I am just writing up my MSc thesis and want to explain the dimensionless Hubble parameter that I have been using through my work. I understand that you take the valuefor the Hubble "constant" and then divide by 100km/sec/Mpc to leave get a value which has no units. There seems to be...

It seems (to me) that parameters are also kind of variables in descriptions of physics. I am confused what makes a paramater different from a variable. Can anybody please explain this?

Hi, this is not based on detailed work but just an idea which arised comparing causal dynamical triangulations and loop quantum gravity. In CDT it seems reasonable to treat spacetime as a fractal. That means there is no limit or minimum length in the triangulations, but the triangulations...

hi all, the situation is this: i have a conditional PDF f_{X|(D,S)}(x|d,s) and the unconditional PDFs D and S, f_{D}, f_{S}. Now, I can marginalize the joint PDF f_{X,D,S}=f_{X|(D,S)}f_{D}f_{S} by integrating over d and s over their respective supports. What I'm really interested in is a...

This is a significant discovery that something is fundamentally controlling and ordering the properties of spiral and disk gaseous galaxies. Elliptical galaxies have no gas and no star formation. The question is not only what but how is the unknown parameter controlling spiral and disk galaxy...

I have a single parameter discrete probability distribution defined over the domain of non-negative integers with pmf in k of: Pr(k;L) = \frac{L^{k}}{k! * k! * I_{0}(2*\sqrt{L})} Where I_{0}() is the modified Bessel function of the first kind with order 0. I do know that E(k^{2}) = L...

How to compute \beta = arg min_\beta \sum_{i=1}^N {|y_i - x_i^T \beta|

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 [FONT="Courier New"]foo as follows: [FONT="Courier New"]\newenvironment{foo}[2]{\begin{tabular}{*{#1}c*{#2}r}}{\end{tabular}} I can write [FONT="Courier New"]\begin{foo}{4}{3}...

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 -...

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...

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 = [SIZE="5"]∫ |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...

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: