Relation Definition and 1000 Threads

Hey PF, I'm just being stupid today, because I can't figure out the way HR diagram is constructed, hope you guys can help. So suppose that you complete an observation in several different filters, and you need to work out the luminosity and temperature for each object in your field of view...

Hi all, so my question is can i carryout normal algebraic operations on derivatives, for example: v=ds/dt and a=dv/dt then eliminating dt a=(dv/ds) *v then, a *ds= v*dv is that how you derive the relationship between acceleration, velocity and displacement?

Here is the question: Here is a link to the question: Equivalence Relation question? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

Homework Statement A particle moves counterclockwise around the ellipse with equation 9x^2 + 16y^2 = 25. a). In which of the four quadrants in dx/dt > 0? Explain. b). Find a relation between dx/dt and dy/dt. c). At what rate is the x-coordinate changing when the particle passes the point...

Please help me in proving the following expression H_{2n}(x)=(-1)^n2^{2n}n!L_n^{-\frac{1}{2}}(x^2) where H_n is the Hermite polynomial and L_n^{-\frac{1}{2}} is the associated Laguerre polynomial.

https://www.google.com/search?hl=pt-PT&q=potential+energy+curve&tbm=isch&tbs=simg:CAQSWgmiv8BdfMuabhpGCxCwjKcIGjQKMggBEgzUBt8GogeoB6cHpgcaINsvJGealnimdPrsI3wtVoz6gqeyB8qrabdVeAx3e1vHDAsQjq7-CBoADCGpFP3k7rrt1w&sa=X&ei=sW4uUd7TDY6xhAelv4CIDg&ved=0CCYQwg4&biw=1366&bih=643#imgrc=or_AXXzLmm6FRM%3A%3Bq...

Here is the question Here is a link to the question: 2nd order homogeneous linear recurrence? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

For part b), I can see that, as p = \frac{E}{c}, then a photon with twice the momentum must have twice the energy. However, I cannot see the answer to part a). My book states that k_2 = 4k_1, but I would have thought that, as per the answer to b), the KE is just twice that of the other, not four...

I know that function is a type of relation. What i acctually need to know is that; Are these relations Equivalent all the times?, or it depends on the types of function?

hey all i know and understand the component of curl/line integral relation as: curlF\cdot u=\lim_{A(C)\to0}\frac{1}{A(C)} \oint_C F\cdot dr where we have vector field F, A(C) is the area of a closed boundary, u is an arbitrary unit vector, dr is an infinitely small piece of curve C my...

A hot-air balloon has just lifted off and is rising at the constant rate of 1.8 . Suddenly one of the passengers realizes she has left her camera on the ground. A friend picks it up and tosses it straight upward. If the passenger is 3.1 above her friend when the camera is tossed, what is the...

Homework Statement 'Show that row equivalence is an equivalence relation'. Homework Equations The definition for 'row equivalence' given in the text is, 'two augmented matrices corresponding to linear systems that actually have solutions, are said to be (row) equivalent if they have the...

Homework Statement let X = {1,2,3,..,10} define a relation R on X x X by (a,b)R(c,d) if ad=bc. show that R is an equivalence relation on X x X. Homework Equations The Attempt at a Solution I think that the R have to be reflexive (because ad=bc). Eg. one of the subset is (1,1)...

Homework Statement (b) A steel alloy has an ultimate tensile strength of 820MN/m2 and a fatigue endurance limit of 390MN/m2. The steel is used in a fatigue application in which the alternating stress is 0.3 times the mean stress. Using the Goodman method with a factor of safety of 1.5...

Dear ForumersI am having a bit problem understanding the phase relation between current source and the generated eletromagnetic field components. Assume a very small current element( a very small current running in direction x)(essentially an electric dipole) in a non-homogenous loss periodic...

One of stokes relation is that r=r'. What does this mean exactly? Is the phase difference between incident beam and reflected beam on a boundary between 2 mediums of different refractive indices ∏??

Homework Statement A planet orbits a massive star in a highly elliptical orbit, i.e, the total orbital energy is close to Zero. The initial distance of closest approach is 'Ro'. Energy is dissipated through tidal motions until the orbit is circularized with a final radius of 'Rf'. Assume the...

Can we approach spin by gradient. For example, spin 1/2 can be written as 180 degree turning in 360 degree space while spin 2 is 720 degree turning in 360 degree space? If I have a ball spinning with angular momentum perpendicular to rotation plane, what is the spin value of the ball? Can some...

Homework Statement This is part of the derivation of the direction of rotation of an ellipse in EM wave polarization. I need to find the direction of the change of phase \psi of the electric field vector with increase of time t. To make the long story short, for example: \psi\;=\...

Homework Statement Determine the result of the integral without using the Fundamental Theorem of Calculus: ##\displaystyle\int_{-\pi}^{\pi} \sin^2{t} \cos{2t} dt##, given the orthonormal basis ##\left\{ \dfrac{1}{\sqrt{2}}, \cos{t}, \cos{2t} \right\}##. Homework Equations Parseval's...

Let A ∈ Mn×n(F ) Why dim span(In, A, A2, A3, . . .) = deg(mA)?? where mA is the minimal polynomial of A. For span (In,A,A2...) I can prove its dimension <= n by CH Theorem but what's the relation between dim span(In,A,A2...)and deg(mA)

1. The problem statement: Show that if the operator relation e^(ipa/ħ)xe^(-ipa/ħ) = x+a holds. The operator e^A is defined to the ∞ e^A= Ʃ(A^n)/n! n=0 [Hint: Calculate e^(ipa/ħ)xe^(-ipa/ħ)f(p) where f(p)is any function of p, and use the representation x=iħd/dp]...

On a smooth triangulation of a manifold differential forms can be viewed as real cochains by integration. The wedge product of two forms gives another real cochain. So does their cup product. - are they cohomologous? - Is there a limiting process that relates them?

I posted a link to this topic, so the OP could find my response. Here is a link to the original question: Recursive formula help on real world situations? - Yahoo! Answers Let $A(t)$ represent the amount, in mg, of antibiotic in Jonah's bloodstream at time $t$, measured in hours. With a...

Can the Planck relation, and the Heisenberg and the time-energy uncertainty principles be derived, or produced, from the equations of General Relativity?

Finally I found the time to write my account on the interpretation of the Heisenberg uncertainty principle vs. the question whether it can be interpreted as Heisenberg did in his very first paper on the subject. Although it is well known that this interpretation is not compatible with quantum...

Hi there. I am having trouble interpreting the Kolmogorov K41 scaling relation for homogeneous and isotropic turbulence: S_{p}(l) = <\delta u(l)^{p}> = <|u(r+l) - u(r)|^{p}> \propto (\epsilon l)^{p/3} where l is the length of displacement between two points under consideration in the...

Homework Statement Calculate the spin wave dispersion relation Ek for the ferromagnetic Heisenberg model with jtot = 1/2 Assume a 1d square lattice and interactions of strength J between nearest neighbours and zero elsewhere Homework Equations H|k> = [E0 +2jtot\sum J(r)(1-Exp(ik.r) ]...

Hi, The Fourier series can (among others) expressed in terms of sines and cosines with coefficients a_n and b_n and solely by sines using amplitudes A_n and phase \phi_n. I want to express the latter using a_n and b_n. Using a_n = A_n \sin(\phi_n) \\ b_n = A_n \cos(\phi_n) I...

Hey All! My question is regrading a subtle observation that i made when i was straing at my "spring coil type" room heater. Accidently i pulled up some stands of heating coil spring to make them straight section (obviuosly when it was switched off). Then, when i passed current through it...

I have a very trivial question to ask and it would be great if someone could help me in this. The statement that '3-point amplitudes' and the location of poles are sufficient to determine any n-point amplitude at tree level is confusing to me. Don't I also need to know 4-point amlitudes, for...

What is the commutator [\hat{A}\hat{B}, \hat{C}\hat{D}] equal to? How to distribute what's inside?

Hello, What does the Faber Jackson relation tells? Does it establish the relation between: higher the Luminosity, higher the velocity dispersion? Does it calculate in Elliptical galaxies? What does Tully-Fisher relation explains? -- Shounak

what is the "form" of the following recursion relation? Hi all, I have a recursion relation I am trying to solve: {X_n} = \frac{1}{{1 - {\alpha _0} \cdot {X_{n - 1}}}} \to {X_n} = ? What is the "mathematical form" of this recursion-relation? E.g., I know what a homogeneous, linear...

May I know what is the difference between the dispersion relation for 100 and 001 on the E-K diagram? Can i say 001 has lesser dispersion? But why is it so?

Homework Statement Find all the primes p and q such that p^2-p-1=q^3 The Attempt at a Solution Trying out the first prime number 2, it is clear that p>q and that the difference is larger than 1. Then when factorizing it p^2-p=q^3+1 \Rightarrow p(p-1)=(q+1)(q^2-q+1), I get that p must...

Homework Statement Find the matrix that represents the given relation. Use elements in the order given to determine rows and columns of the matrix. R on {2, 3, 4, 6, 8, 9, 12} where aRb means a|b. Homework Equations The Attempt at a Solution 1 0 1 1 1 0 1 0 1 0 1 0 1 1 0 0...

Given a group G acting on a set X we get an equivalence relation R on X by xRy iff x is in the orbit of y. My question is, does some form of "reciprocal" always work in the following sense: given a set X with an equivalence relation R defined on it, does it always exist some group G with some...

Homework Statement Compute the numerical constant C for an electron gas (take Z = 6 and A = 12) and determine the radius of a white dwarf whose mass is 0.6 solar masses. h\ =\ 6.62606876(52)\ \times\ 10^{-34}\ Jh\ =\ 6.62606876(52)\ \times\ 10^{-34}\ J\ s\ s m_{e}\ =\ 9.10938188(72)\...

Homework Statement Assume a relation P that is negatively transitive on a set X that is not empty. Define the binary relation R on X by xRy iff y P x is false. Prove that R is transitive.Homework Equations Negative Transitivity: xPz \rightarrow xPy \vee yPz Like in the previous thread...

Homework Statement Assume a relation P that is asymmetric on a set X that is not empty. Define the binary relation R on X by xRy iff y P x is false. Prove that R is complete Homework Equations Asymmetry: xRy \rightarrow \neg (yRx) Now, I think I got a proof, but I am not sure...

Do you believe genetics can cause one to have a particular accent in a given language? Or are accents only related to post-birth personal development? Are there ethnicities having anatomically distinct voice boxes, that have more difficulty in emulating specific accents? I tend to...

I was trying to Go from the uncertainty principle to its energy-time counter part. i know the maths is a bit off,but the idea is correct? dx=position p=momentum e=energy \upsilon=frequency \lambda=wavelength c=velocity of electromagnetic radiations dt=time now , \lambda=h/p....(i)...

Should I in any way find this intuitive? Apart from the fact that the idea of a commutation relation resembles the idea of a poisson bracket for operators I can't see how I should find it intuitive.

i don't know in which section it belongs, so i am putting it here... according to various theories proposed by various researchers, time travel depends on the speed of light. as far as i have read/heard - i) anything traveling faster than the speed of light moves back in time. ii) anything...

Homework Statement find the relationship between the 2 particles' accelerations. Homework Equations m1=20kg m2=40kg wheel doesn't weigh but can move. both particles move with friction. μs=μk=0.2 F(t)=98e0.1t The Attempt at a Solution I came up with 3 equations...

Homework Statement Suppose f:R^2 - {0} → R is a differentiable function whose gradient is nowhere 0 and that satisfies -y(df/dx) + x(df/dy) = 0 everywhere. a) find the level curves of f b) Show that there is a differentiable function F defined on the set of positive real numbers so that...

This is a conceptual question on the region of convergence (ROC) and the inverse Laplace transform (ILT). Here the bilateral laplace transform (LT) and the ILT are given by F(s)=L\{f(t)\}=\int_{-\infty}^{+\infty} f(t) e^{-st} dt and f(t)=L^{-1}\{F(s)\}=\frac{1}{i...

Friction causes a torque that opposes angular momentum. It gets reduced. how can we derive a relation connecting these. friction starts with maximum and becomes zero. angular velocity and its corresponding momentum decreases maximum in the beginning and increases towards the end. the radial...

ok, so, I know e=mc2 is a way i can find what quantity of energy a mass has. and i know that as objects increase in speed they become more massive, which i assume is also elegantly portrayed in this equation. but, this kind poses a problem for me, because i am wondering how much velocity...