Function Definition and 1000 Threads

  1. A

    A Average transverse momentum as a function of the longitudinal momentum

    Hello everybody! I am working on a code in which I need to study the dependence of ##<p_T>## vs ##p_L## (the average transverse momentum and the longitudinal momentum of a particle). I am looking for references, papers, books, etc. concerning this topic, but I have not been so lucky. My...
  2. L

    How does this composite function simplify to 2(2^x) ?

    f(x)=2xand g(x)=2^x Find the composite function of fg(x) fg(x) =f(g(x)) =f(2^x) =2(2^x) I don’t understand how this in turn equals to 2^(x+1) [Moderator's note: Moved from a technical forum and thus no template.]
  3. T

    Python Shifting an array one postion to the left -- Non Function Vs Function

    I am currently doing some task on a website called Codility (link and bottom of post). The task basically ask for me to create an algorithm to shift an array to the left K times (Full details below). Which seem to work for a non function but I still seem to be shifting it wrong as the output is...
  4. V

    Solve for x with a trigonometric function

    Homework Statement: Solve for x. Homework Equations: sin(3x)= -1/2 sin(3x) = -1/2 3x = sin-1(-1/2) 3x = -π/6 x = -π/18 x = -π/18 + 2π/3 = 11π/18 11π/18 + 2π/3 = 23π/18 11π/18 + (2π(4))/3 = 35π/18 The solutions I obtained were 23π/18 and 35π/18. Are these correct? I'm not entirely sure...
  5. S

    MHB Find cost revenue and profit function

    Dear All, Here is my question. The marketing department estimates that if the selling price of the new product is set 40 dollar per unit, sales will be 400 units per week. If the selling price is 20dollar per unit, sales will be 800 units per week. The production dept estimates that variable...
  6. adosar

    I Position of Particle in Special Relativity (A vs B)

    Recently I have come into Special Relativity and specifically Lorentz transformation. Let's assume two frames A and B moving relative with speed ##v##. The position of a particle moving with respect to B is given by ##x′=f(t′)=3t′##. What is the function of position ##x=f(t)## of the particle...
  7. PainterGuy

    B Decomposition of a function into even and odd parts

    Hi, I understand how any function could be decomposed into even and odd parts assuming the function isn't a purely even or odd to start with. It's just like saying that any vector in x-y plane could be decomposed into its x- and y-component assuming it doesn't lie parallel to x- or y-axis...
  8. H

    Green's function and the resistance across a Hypercube

    Homework Statement: I do know how to solve the resistance network problem in two dimensions. However, in this problem they want it in 3 dimensions and higher and I don't know how to do that Homework Equations: - In the picture you can see the solution to the two dimensional version
  9. T

    Python Converting List and tuples using str() function

    I am currently working my way through some w3schools python exercise on tuples and lists etc and one question was to write a program to converted a tuple to a string. Now originally I used the str() function on the tuple and printed the result. I then used the string in a for loop for a...
  10. Ranku

    I Heavier bosons and their function and detection

    Heavier bosons like ##W## or ##H## require high energy accelerator to be detected. Yet these bosons fulfill their function in the ambient energy of the universe. Why is it that their detection takes high energy environment but their function is possible in lower ambient energy?
  11. karush

    MHB 6.2.15 Find the domain of each function.

    $\textsf{6.2.15 Find the domain of each function.}$ (a) $f(x)=\dfrac{1-e^{x^2}}{1-e^{1-x^2}}$ set the denominator to zero and solve $1-e^{1-x^2}=0$ then $x=1,-1$ from testing the domain is $(-1,1)$(b) $f(x)=\dfrac{1+x}{e^{ \cos x}}$ set $e^{\cos x}=0$...
  12. H

    B Question about expanding a function to first order

    If we have a function ##f(x+\Delta x)## where ##\Delta x << x##, is it valid to approximate this as: $$f(x + \Delta x) \approx f(x) + f'(x)\Delta x$$ even if ##\Delta x## is not necessarily small? If not, what is the valid expansion to first order?
  13. Wrichik Basu

    Python Python 3.7.4 lacks a proper linspace function?

    Basically, I wanted to create a Numpy array with linearly spaced integers between 0 and 3, the increment being 0.01. Yes, I know Numpy offers a linspace function. I used it like this: x = np.linspace(0, 3, num=300) (where np is numpy), and got this: I know that the numbers cannot be exact...
  14. D

    I Help discretizing this PDE (stream function)

    I have a PDE that I want to solve for a stream function ψ(j,l) by discretizing it on a 2D annulus grid in cylindrical coordinates, then solving with guas-seidel methods (or maybe a different method, not the point): (1/s)⋅(∂/∂s)[(s/ρ)(∂ψ/∂s)] + (1/s2)⋅(∂/∂Φ)[(1/ρ)(∂ψ/∂Φ)] Where s and Φ are...
  15. Bheshaj

    I Function of a Battery in Simple Circuits

    In a simple circuit with battery connected to a resistor or a combination of resistors where is the electric field directed . What do we mean when we say battery creates a potential difference between two points in a conductor? And by the statement that battery moves positive charge from low...
  16. PainterGuy

    MATLAB Replacing the "quad" function with "integral" doesn't work in Matlab

    Hi, I was trying to numerically integrate the following inverse Fourier transform integral,, using the code below. The plot is also shown below. The plot looks good which means the result is good as well. By the way, I was getting a warning which I quote below the code. % file name...
  17. H

    I Wave function when there is coupling between spin and position

    Why can't the general state, in the presence of coupling, take the form $$\psi_-(r)\chi_++\psi_+(r)\chi_-$$ where ##\psi_+(r)## and ##\psi_-(r)## are respectively the symmetric and anti-symmetric part of the wave function, and ##\chi_+## and ##\chi_-## are respectively the spinors representing...
  18. karush

    MHB 219 AP Calculus Exam Inverse function

    Let $f(x)=(2x+1)^3$ and let g be the inverse of $f$. Given that $f(0)=1$, what is the value of $g'(1)?$$(A)\, \dfrac{2}{27} \quad (B)\, \dfrac{1}{54} \quad (C)\, \dfrac{1}{27} \quad (D)\, \dfrac{1}{6} \quad (E)\, 6$ok not sure what the best steps on this would be but assume we first find...
  19. Lynch101

    B Entanglement & Wave Function Collapse

    This thread is to look at the notion of wave function collapse and relativity of simultaneity. The other thread I started on QFT has helped to clarify a lot, so hopefully this one can do the same. I may have this all wrong, but I will outline my question and hopefully someone can point out...
  20. Eclair_de_XII

    If a one-sided limit of a function doesn't exist, how can a function

    Instinct tells me to just plug in the number, say the limit is zero, and be done with it. But at the same time, while reading the statement from the "Relevant equations" section of this post, I cannot feel but feel some doubt as to whether or not this is the right approach. I mean, only the...
  21. Wrichik Basu

    Python Question about a function call with multiple arguments

    Recently in college, we have started learning python. I found that the print statement can accept multiple variables. For example, if I have variables x1, x2 and x3, I can write print(x1, x2, x3) in python. Something similar exists in Matlab as well. I have learned Java for nearly four years...
  22. Jamister

    I How can the photon wave function be described?

    Fermions such as the electron and proton can be described by wave function in momentum and in position, and it is possible to get the momentum wavefunction from space wave function and vice versa by Fourier Transform. what about photons? can photons be described by position wave function? If...
  23. karush

    MHB 217 AP Calculus Exam continous function with k

    217 $f(x)=\begin{cases} \dfrac{(2x+1)(x-2)}{x-2}, &\text{for } x\ne 2 \\[3pt] k, &\text{for } x=2 \\ \end{cases}$$(A)\,0\quad(B)\,1\quad(C)\,2\quad(D)\,3\quad(E)\,5\quad$
  24. Vicol

    Probability density function in classical mechanics

    Probability density function plays fundamental role in qunatum mechanics. I wanted to ask if there is any analogous density function in classical mechanics. Obviously if we solve Hamilton equations we get fully deterministic trajectory. But it should be possible to find function which shows...
  25. Sophrosyne

    Is the concept of "wave function collapse" obsolete?

    Summary: In the past, physicists talked of the phenomenon of "wave function collapse" very freely, whereas now there seems to be some reservation about it. Why? In reading older popular physics literature, physicists used to talk about "wave function collapse" freely and more often...
  26. Plat

    Radiometer rotation speed as function of pressure

    I am experimenting with using a radiometer as an approximate indicator of pressure in my homemade high vacuum system, running a small turbo pump. I am interested in the relationship between pressure and vane rotation speed, with light intensity being constant. I have only been able to find...
  27. S

    I Assigning a value for integrating a divergent oscillatory function to infinity

    There are meaningful ways to assign values to things like 1 - 1 + 1 + ... or 1 - 2 + 3 - 4 + ... In a similar spirit, is it possible to assign a value to the integral of a function like this: ##f(x)=x*sin(x)## or this one: ##g(x)=Re(x^{1+5i})## (Integrals from some value, say zero, up...
  28. D

    Is this complex function analytic?

    ## u_x = 3x^2 -3y^2 ## and ## v_y = -3y^2-3x^2 ## ## u_y = -6xy## and ## v_x = -6xy## To be analytic a function must satisfy ##u_x = v_y## and ##u_y = -v_x## Both these conditions are met by x=0 and y taking any value so I think the functions is analytic anywhere on the line x=0 However...
  29. CricK0es

    Expanding a function for large E using the Taylor Expansion technique

    I have been playing around with Taylor expansion to see if I can get anything out but nothing is jumping out at me. So any hints, suggestions and preferably explanations would be greatly appreciated as I’ve spent so so long messing around with it and I need to move on... But as always, thank you
  30. C

    I Differences between the PCA function and Karhunen-Loève expansion

    Hello everyone. I am currently using the pca function from MATLAB on a gaussian process. Matlab's pca offers three results. Coeff, Score and Latent. Latent are the eigenvalues of the covariance matrix, Coeff are the eigenvectors of said matrix and Score are the representation of the original...
  31. maajdl

    A Getting structure data from a partition function?

    Hello, From wikipedia, this is the partition function for a "classical continuous system": This is the pillar of classical statistical physics, but it can be seen as a mere kind of "mathematical transform" . It can be used even without thinking to statistics or temperature. If we focus only...
  32. Y

    MHB Understanding the Floor Function: How to Find ⌊0.785⌋

    I am not able to understand what the question asks of me in Q75, part a)
  33. Pencilvester

    I Multiplying two function operators

    I am reading Zettili’s “Quantum Mechanics: Concepts and Applications” and I am in the section on functions of operators. It starts with how ##F(\hat A)## can be Taylor expanded and gives the particular and familiar example: $$e^{a \hat A} = \sum_{n=0}^\infty \frac{a^n}{n!} \hat A^n...
  34. Jamister

    A Electron Vertex Function in QED

    In Peskin book they calculate the QED Vertex Function named Gamma which depend on two scalar functions called form factors F1(q^2), F2(q^2). they are calculating F1(q^2) and they do not really finish calculating for what I understand. They are just showing the Infrared divergent is canceled by...
  35. I

    Epsilon delta proof of the square root function

    Let ##\varepsilon > 0## be arbitrary. Now define ##\delta = \text{min}\{\frac{a}{2}, \varepsilon \sqrt{a}\}##. Now since ##a>0##, we can deduce that ##\delta > 0##. Now assume the following $$ 0< |x-a| < \delta $$ From this, it follows that ##0 < |x-a| < \frac{a}{2} ## and ##0 < |x-a| <...
  36. G

    A Correlation function of a Klein-Gordon field

    First, let me introduce the notation; given a Hamiltonian ##H## and a momentum operator ##\vec{P}##, and writing ##P=(H,\vec{P})##. Let ##|\Omega\rangle## be the ground state of ##H##, ##|\lambda_\vec{0}\rangle## an eigenstate of ##H## with momentum 0, i.e. ##\vec{P}|\lambda_\vec{0}\rangle=0##...
  37. Robin04

    Asymptotic expansions of the sine function

    There are no restrictions for ##a,b,f_1,f_2##. One solution is the first order Taylor series expansion of course with ##f_1(a)=a,f_2(b)=b##, but are there any other solutions? I tried the Bhaskara formula but I couldn't express it in this form.
  38. S

    Steps from state space to transfer function

    I mean the first question has derivative form and the second is linear form so what the difference here in steps of converting both to transfer function... please need some ellaboration to make sure i am solving correctly or not... is it correct to apply the same rule on both: Transfer function=...
  39. S

    Converting linear state space into a transfer function

    My questions are now... Do the steps of converting this space to transfer function include any laplace ? or just we do get [SI-A]-1 and then transfer function is = C* [SI-A]-1 * B As [1 0] * [s-1/det -0.5/det ; 0.5/det s-0.5/det] * [0; 1] = -0.5/s^2+s+0.5 I mean do we need any laplace after that...
  40. F

    A The partial derivative of a function that includes step functions

    I have this function, and I want to take the derivative. It includes a unit step function where the input changes with time. I am having a hard time taking the derivative because the derivative of the unit step is infinity. Can anyone help me? ##S(t) = \sum_{j=1}^N I(R_j(t)) a_j\\ I(R_j) =...
  41. L

    I Can we truly ignore the existence of quantum objects between measurements?

    We always think in terms of isolated particles. It's better to analyze it with solids. If wave functions were just calculational tools. Molecules like the following still interact by wave functions, right? So how can it be calculational tool? And if it is, then what model do you use to...
  42. dRic2

    The work function and mutual forces between particles

    I tried to apply the chain rule $$X_{ik} = \frac {\partial U}{\partial \xi_{ik}} = \frac {\partial U}{\partial x_{i}} \frac {\partial x_i}{\partial \xi_{ik}} = \frac {\partial U}{\partial x_{i}} $$ and I got the force x-component of the force acting on ##P_i## I guess. but I do not know what...
  43. C

    Question about the PCA function

    Greetings everyone. I have generated a gaussian random process composed of 500 realizations and 501 observations. The used random variables are gaussian normal. I have then applied the pca analysis to that process (Mathwork's help). However, if I plot the histograms of the coeffs I don't find...
  44. sergiokapone

    1D Green function for a charged layer

    I came across an example of a solution to finding the potential of a charged layer using the Green function (here, pdf). The standard algorithm for finding the Green function by boundary conditions for many problems is understandable: \begin{align*} G_\mathrm{Left} = Ax+ B \\ G_\mathrm{Right} =...
  45. L

    I Objective Wave Function and Non-locality

    In interpretations where the wave function represents something real, like Many worlds, Copenhagen with objective wave function and spontaneous objective collapses. I'd like to understand which of them has true non-locality. First. Is Many Worlds not having true non-locality due to the...
  46. Wrichik Basu

    B General form of electromagnetic vertex function in QFT

    I am studying a beginner's book on QFT. In a chapter on electromagnetic form factors, the authors have written, using normalized states, $$\begin{eqnarray} \langle \vec{p'}, s'| j_\mu (x) |\vec{p}, s \rangle \ = \ \exp(-i \ q \cdot x) \langle \vec{p'}, s'| j_\mu (0) |\vec{p}, s \rangle...
  47. Robin04

    I Mean of the derivative of a periodic function

    We have a periodic function ##f: \mathbb{R} \rightarrow \mathbb{R}## with period ##T, f(x+T)=f(x)## The statement is the following: $$\frac{1}{T}\int_0^T f(x)dx =0 \implies \frac{1}{T}\int_0^T\frac{d}{dx} f(x)dx =0$$ Can you give me a hint on how to prove/disprove it? The examples I tried all...
  48. M

    Developing a multivariable function

    Hello! I am facing a difficulty into developing a multivariable function of a dependent variable "x". Let's assume that "x" is a function of 6 independent variables a,b,c,d,e,f,g. From experimental data i have developed 6 functions, each representing how "x" changes by each of the paremeters...
  49. dRic2

    How does a cooling tower function?

    So I'm having trouble understanding the physics behind evaporative cooling. This is what I know: I want to cool some water so I nebulize it and I let an air flow (coming from the outside) pass through this mist of water. Now some water has to evaporate. Here I am stuck because I don't understand...
Back
Top