Continuous Definition and 1000 Threads

  1. R

    I How does one formulate continuous probabilities/pdfs?

    Discrete examples are easy enough. Toss a coin, 1/2, toss a die, 1/6. Continuous examples, Probability of a nucleus decaying during observation, 1-exp(-λt), Probability of a neutron moves x without interaction, exp(-Σx), where Σ can be assumed to be the inverse of the mean free path i.e. the...
  2. J

    MHB Can I Find Examples for Continuous Improvement?

    Need help for the two parts! Thanks!
  3. J

    MHB Find Limit of cos(x) with Inequalities | Part (b) Help

    Need advice on how to find lim of cos(x) using the inequalities provided. Also part (b) for help. Thanks.
  4. T

    Expected bounds of a continuous bi-variate distribution

    Homework Statement [/B] ##-1\leq\alpha\leq 1## ##f(y_1,y_2)=[1-\alpha\{(1-2e^{-y_1})(1-2e^{-y_2})\}]e^{-y_1-y_2}, 0\leq y_1, 0\leq y_2## and ##0## otherwise. Find ##V(Y_1-Y_2)##. Within what limits would you expect ##Y_1-Y_2## to fall? Homework Equations N/A The Attempt at a Solution...
  5. Z

    Continuous random Var range and example

    Homework Statement Why we use range with continuous random and why is time continuous var and why we associate a range with it? Homework Equations Theoreticl topic The Attempt at a Solution Hi, I can't understand about the continuous random var and its range. It says that measurable values are...
  6. J

    MHB Can Dividing by Sin x Help Prove Continuity at x = 0?

    Not sure how to do this question. Help needed. Thanks
  7. J

    MHB Is Showing One ε Enough to Prove Discontinuity?

    Appreciate the help needed for the attached question. Thanks!
  8. T

    Metric space of continuous & bounded functions is complete?

    Homework Statement The book I'm using provided a proof, however I'd like to try my hand on it and I came up with a different argument. I feel that something might be wrong. Proposition: Let ##<X,d>## be a metric space, ##<Y,D>## a complete metric space. Then ##<C(X,Y), \sup D>## is a complete...
  9. T

    I Proof Explanation: Showing an extension to a continuous function

    I am reading Kaplansky's text on metric spaces and this part seems redundant to me. It was stated below (purple highlight) that we need to show that the convergence of ##(f(a_n))## to ##c## is independent of what sequence ##(a_n)## converges to ##b##, when trying to prove the claim ##f(b)=c##...
  10. FallenApple

    A Continuous output: logistic vs linear regression

    so say I suspect that there is a positive trend in the data from the scatter plot. Say the output y is continuous. A linear regression would give me a possitive estimate of the slope. For a one unit increase in x, I would get a so and so increase in y. I can also split the data for the y...
  11. T

    Show that ##\frac{1}{x^2}## is not uniformly continuous on (0,∞).

    Homework Statement Show that ##f(x)=\frac{1}{x^2}## is not uniformly continuous at ##(0,\infty)##. Homework Equations N/A The Attempt at a Solution Given ##\epsilon=1##. We want to show that we can compute for ##x## and ##y## such that ##\vert x-y\vert\lt\delta## and at the same time ##\vert...
  12. S

    B An elementary confusion on discrete or continuous variable

    The question is simply posed as " identity the variables as discrete or continuous. 1) Mark of a student in an examination. 2) Family income." What I think: 1) There must be a minimum gap between two possible consecutive marks that the examiner can assign. Eg. Suppose that there are N students...
  13. N

    A TD perturbation - state initially in continuous part

    Hi everyone, I am doing a time dependent perturbation theory, in a case when the electron is prepared in a state of the continuous part of the energy spectrum. Existence of the discrete part and the degeneracy of the continuous part is irrelevant at the moment and will not be considered...
  14. S

    A Can quantum cellular automata simulate quantum continuous processes?

    Can quantum cellular automata/quantum game of life simulate quantum continuous processes in the continuous limit? At the end of this article: https://hal.archives-ouvertes.fr/hal-00542373/document it is said that: "For example, several works simulate quantum field theoretical equations in the...
  15. T

    Showing that an exponentiation is continuous -- Help please....

    Homework Statement Let ##p\in\Bbb{R}##. Then the function ##f:(0,\infty)\rightarrow \Bbb{R}## defined by ##f(x):=x^p##. Then ##f## is continuous. I need someone to check what I've done so far and I really need help finishing the last part. I am clueless as to how to show continuity for...
  16. A

    A Rigorous transition from discrete to continuous basis

    Hi all, I'm trying to find a mathematical way of showing that given a complete set $$\left |a_i\right \rangle_{i=1}^{i=dim(H)}∈H$$ together with the usual property of $$\left |\psi\right \rangle = ∑_i \left \langle a_i\right|\left |\psi\right \rangle\left |a_i\right \rangle ∀ \left...
  17. Levi Franco

    B Basic Question about absolutely continuous functions

    My question is maybe elementary but I don't know the answer. I have a function f absolutely continuous in (a,c) and in (c,b), f continuous in c. Is f absolutely continuous in (a,b)? I think the answer is negative but I can't find a counterexample. I really apreciatte your help.
  18. V

    B Is space is continuous or discrete?

    I was watching a video where well known physicist Lisa Randall said that we still don't know whether space is continuous or discrete. My question is, how do we find whether space is continuous or discrete?? What type of experiments are possible? Is it being done now?? I am thinking this may be...
  19. I

    Discretize this continuous time linear system

    Homework Statement I need to find the discrete time equivalent of the following system: \begin{bmatrix} \ddot{x} \\ \dot{x} \\ \ddot{\theta} \\ \dot{\theta} \end{bmatrix} = \begin{bmatrix} 0 & 0 & 0 & 4.2042857 \\ 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 105.1071428 \\ 0 & 0 & 1 & 0 \end{bmatrix}...
  20. J

    Is this function continuous and differentiable?

    Homework Statement Homework Equations Solve using limits. Function is continuous if it's graph is continuous throughout. here the (x-1) term gets canceled in numerator and denominator. So we have a continuous graph of (x+1). The Attempt at a Solution The (x-1) term gets canceled from...
  21. Dor

    I What should be continuous at the interface of two materials?

    At the interface between: 1) conductor/conductor 2) conductor/semiconductor (or dielectric) 3) semiconductor/semiconductor (or dielectric/dielectric) What quantity should be continuous? Is it the electrochemical potential, only the chemical potential or is it the electric potential? Since they...
  22. Mr Davis 97

    Show that this piecewise function is continuous at 0

    Homework Statement ##f(x) = x \sin (\frac{1}{x})## for ##x \ne 0## and ##f(0) = 0##. Prove that this function is continuous at 0. Homework EquationsThe Attempt at a Solution First, I need to look at the quantity ##|f(x) - f(0)|##. However, I am not completely sure how to proceed. I would think...
  23. M

    Rule de l'Hôpital - Continuous and Differentiable

    Homework Statement Prove that ##h: [0,\infty) \rightarrow \mathbb R, x \mapsto \begin{cases} x^x, \ \ x>0\\ 1, \ \ x = 0\\ \end{cases} ## is continuous but not differentiable at x = 0. The Attempt at a Solution To show continuity, the limit as x approaches 0 from the right must equal to 1...
  24. R

    Assume that f is a continuous, real-valued function

    Assume that f is a continuous, real-valued function defined on a metric space X. If {xn} is a sequence in X converging to x, prove that Limn→∞f(xn) = f(x). Here is my attempt, but I am not sure if it is correct.
  25. P

    MHB How can i set this problem as a continuous markov chain?

    I request your help in order to know, how can i configure this problem as a continuous markov chain, need to define the main variable, the states, transition rates, and the matrix. I thought that it could be relationed with the independent status of the machines, because if the machine 1 is...
  26. M

    MHB Gamma function is convergent and continuous

    Hey! :o I want to show that the Gamma function converges and is continuous for $x>0$. I have done the following: The Gamma function is the integral \begin{equation*}\Gamma (x)=\int_0^{\infty}t^{x-1}e^{-t}\, dt\end{equation*} Let $x>0$. It holds that...
  27. Y

    Consequences of time not being continuous

    Homework Statement Given that the phenomena of time is non continuous, despite it often being considered as being so, what are the consequences of this? It seems that the foundation of mathematics that describes the physical world assumes that time is continuous, which we believe now to be...
  28. F

    Convergence of a continuous function related to a monotonic sequence

    Homework Statement Let ##f## be a real-valued function with ##\operatorname{dom}(f) \subset \mathbb{R}##. Prove ##f## is continuous at ##x_0## if and only if, for every monotonic sequence ##(x_n)## in ##\operatorname{dom}(f)## converging to ##x_0##, we have ##\lim f(x_n) = f(x_0)##. Hint: Don't...
  29. S

    Pressure in a tank with continuous flow

    I feel like this is easy to answer but I'm coming up with answers I don't trust. Basically, I have a tank of air where I want to keep the pressure at a certain value. Let's say 1 psig for the sake of argument. I have a 1/2" ID hose connecting to inlet flow to the tank and an outlet hose of 3/4"...
  30. qttv

    A Classical Mechanics: Continuous or Discrete universe

    Good morning. The question of the "continuous" or "discrete" nature of the universe is the subject of diatribe among the greatest physicists in the world. I would like to discuss the same topic, but asking a question about the aspect of continuum in classical mechanics. The use of mathematical...
  31. O

    Step potential, continuous wave function proof

    Homework Statement I am being asked to show that the wave function ψ and dψ/dx are continuous at every point of discontinuity for a step potential. I am asked to make use of the Heaviside step function in my proof, and to prove this explicitly and in detail. Homework Equations...
  32. B

    I Continuous Lensing Models: Discrete Data

    Hello, I am not sure if this question is better suited to the mathematics section, but I thought it would be easier to explain the problem here. In Schneider, Kochanek and Wambsganss's "Gravitational Lensing: Strong Weak and Micro" pages 279-280, they derive a relation for determining the...
  33. Math Amateur

    MHB Linear Mappings are Lipschitz Continuous .... D&K Example 1.8.14 .... ....

    I am reading "Multidimensional Real Analysis I: Differentiation" by J. J. Duistermaat and J. A. C. Kolk ... I am focused on Chapter 1: Continuity ... ... I need help with an aspect of Example 1.8.14 ... ... The start of Duistermaat and Kolk's Example 1.8.14 reads as...
  34. Math Amateur

    MHB The Euclidean Norm is Lipschitz Continuous .... D&K Example 1.3.5 .... ....

    I am reading "Multidimensional Real Analysis I: Differentiation" by J. J. Duistermaat and J. A. C. Kolk ... I am focused on Chapter 1: Continuity ... ... I need help with an aspect of Example 1.3.5 ... ... The start of Duistermaat and Kolk's Example 1.3.5 reads as...
  35. G

    I Disctrete vs continuous spectrum

    I’ve been digging around trying to get at the physical basis for the black body spectrum. Say I have a neutral gas,non ionized. This has its own discrete spectrum. Are the mechanisms of line broadening the reason why we seek continuous spectrum in the back body curve? That’s question 1. No 2...
  36. Math Amateur

    MHB A Further Question on Proper and Continuous Mappings .... D&K Theorem 1.8.6 ....

    I am reading "Multidimensional Real Analysis I: Differentiation" by J. J. Duistermaat and J. A. C. Kolk ... I am focused on Chapter 1: Continuity ... ... I need help with another aspect of the proof of Theorem 1.8.6 ... ... Duistermaat and Kolk"s Theorem 1.8.6 and the preceding definition...
  37. Math Amateur

    MHB Proper and Continuous Mappings in R^n .... ....

    I am reading "Multidimensional Real Analysis I: Differentiation" by J. J. Duistermaat and J. A. C. Kolk ... I am focused on Chapter 1: Continuity ... ... I need help with an aspect of the proof of Theorem 1.8.6 ... ... Duistermaat and Kolk"s Theorem 1.8.6 and the preceding definition...
  38. Math Amateur

    MHB Continuous Functions and Open Sets .... D&K Example 1.3.8 ....

    I am reading "Multidimensional Real Analysis I: Differentiation" by J. J. Duistermaat and J. A. C. Kolk ... I am focused on Chapter 1: Continuity ... ... I need help with an aspect of Example 1.3.8 ... Duistermaat and Kolk"s Example 1.3.8 reads as follows:In the above example we read the...
  39. J

    Principle of virtual work for continuous systems

    I always thought that the principle of virtual work (PVW) is valid for all structures, including continuous structures (like bars, beams, plates, etc.). However, in his book 'Fundamentals of Structural Mechanics', Hjelmstad states that the PVW is only valid for discrete systems with N particles...
  40. M

    MHB Find a function so that the composition is continuous

    Hey! :o For which real constants $a,b,c$ is the following function $f$ continuous on $\mathbb{R}$ ? $$f(x)=\begin{cases}1+x^2 & \text{ for } x\leq 1, \\ ax-x^3 & \text{ for } 1<x< 2 \\ b & \text{ for } x=2\\ cx^2 & \text{ for } x>2\end{cases}$$ For $a=1, b=-6, c=-\frac{3}{2}$ the function...
  41. I

    Continuous Grey Atmosphere Model

    Homework Statement In the grey atmosphere radiative energy balance model, we replace the multi-layer approximation used above with still simplified but significantly more realistic model involving a continuous atmosphere with a continuously varying temperature. The variation with temperature is...
  42. T

    Why is blackbody radiation continuous?

    Plasmas can emit radiation based on the acceleration of charged particles (which we generally consider as continuous), but for un-ionized matter compounds, transitions are quantized and photons have particular energies. At room temperature, collisional excitations are typically dominant. But if...
  43. Dopplershift

    I Understanding Continuous Variable QKD

    So, I am doing my undergraduate research project in Quantum Cryptography, and I have some confusion in a few areas, especially in the topic of continuous variable quantum key distribution. From what I understand, Discrete Variable - Single photon. That is, for example, the BB84 protocol. Bob...
  44. B

    Gravitational potential energy and continuous matter

    The gravitational potential energy of two massic points ##P_1## and ##P_2## with respective masses ##m_1## and ##m_2## is given by $$U = -G \frac{m_1 m_2}{|| P_2 - P_1 ||}$$ Now I was wondering how this formula could be applied to continuous matter. Let us imagine a very simple case where we...
  45. I

    B Inner product of functions of continuous variable

    I am new to quantum mechanics and I have recently been reading Shankar's book. It was all good until I reached the idea of representing functions of continouis variable as kets for example |f(x)>. The book just scraped off the definition of inner product in the discrete space case and refined it...
  46. G

    Intersecting 2 continuous laser in thin air to create a dot

    I am planning on making an experiment about intersecting continuous wave laser from 2 or more source on 1 point in thin air. The laser i am planning to use is the simple laser diode, pumped with continuous wave, instead of using pulsed wave as in the usual laser pointer as i don't need it to...
  47. B

    Composition of a Continuous and Measurable Function

    Homework Statement Suppose that ##f## and ##g## are real-valued functions defined on all of ##\Bbb{R}##,##f## is measurable, and ##g## is continuous. Is the composition ##f \circ g## necessarily measurable? Homework EquationsThe Attempt at a Solution Let ##c \in \Bbb{R}## be arbitrary. Then...
  48. dextercioby

    I Continuity of the determinant function

    This is something I seek a proof of. Theorem: Let ## \mbox{det}:\mbox{Mat}_{n\times n}(\mathbb{R}) \rightarrow \mathbb{R}## be the determinant function assigned to a general nxn matrix with real entries. Prove this mapping is continuous. My attempt. Continuity must be judged in...
  49. T

    Continuous slab / freely supported slab

    Homework Statement I was told that for continuous slab , it can be only for 2 ways slab. While for freely supported slab , it can be either 2 ways or 1 way slab. P/s : for one way slab , the Ly/Lx <2 . For 2 ways slab , Ly/Lx > 2 . Homework EquationsThe Attempt at a Solution I think it's...
  50. PsychonautQQ

    I Noncompact locally compact Hausdorff continuous mapping

    Self studying here :D... Let X and Y be noncompact, locally compact hausdorff spaces and let f: X--->Y be a map between them; show that this map extends to a continuous map f* : X* ---> Y* iff f is proper, where X* and Y* are the one point compactifications of X and Y. (A continuous map is...
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