Domain Definition and 743 Threads

  1. N

    How do you find the zero-input response in the frequency domain?

    I'm working on a problem and one part of it is finding the zero-input response of a system in the frequency (or "s") domain. The zero-state response can be easily found in the frequency domain, it's just: Y_{zs} = X(S)H(S) But I can't for the life of me find the equation for calculating...
  2. K

    Natural frequency from time domain and frequency domain plot

    Anyone have an idea to find a first and second natural frequency from time domain and frequency domain plot resulting from an accelerometer measuring the vibration in cantilever beam ? Thanks very much :)
  3. Z

    What is the domain of y = log [(4-t)^(2/3)] ?

    Hello to all: I was trying to solve the following question: what is the domain of the function y = log [(4-t)^(2/3)] for Real t. Here is my reasoning: The domain of the log(x) is x>0. I would have interpreted this question in terms of the log of the cubic root of (4-t)^2. Thus, I was...
  4. F

    MHB Expanding the Domain of a Function

    Hi I'm having some problems with an task in my class. It's as follows Given the real function f(x)=Xx for X ∈ (0,∞). Then I'm to expand the definition area to [0,∞), f shall still be continuous. What does f(0) have to be? Thanks for any help :)
  5. sankalpmittal

    Solving Equations with Integer Solutions

    Homework Statement Find the domain of following functions : Note: [.] denotes greatest integer function. {.} denotes fractional part of a function. 1. f(x)=sin-1([x]/{x}) 2. √(2{x}2-3{x}+1) 3. Solve the equation : y=[sinx+[sinx+[sinx]]]/3 [y+[y]]=2cosx Homework Equations...
  6. D

    MHB Integrating on an infinite domain

    How can I integrate this expression: \[ \int_0^{\infty} \mathcal{J}_1(kR)e^{-kz}dk = \frac{1}{R} \left[1 - \frac{z^2}{\sqrt{R^2 + z^2}} \right] \] where \(\mathcal{J}_1\) is the Bessel function of order 1.
  7. D

    MHB Plotting an infinite domain PDE

    Is anyone familiar with plotting an infinite domain PDE where the solution is an integral. Take the solution \[ T(x,t) = \frac{100}{\pi}\int_0^{\infty}\int_{-\infty}^{\infty} \frac{\sinh(u(10-y)}{\sinh(10u)} \cos(u(\xi-x))d\xi du \] How could I plot this in Matlab, Mathematica, or Python? As a...
  8. D

    MHB Why are there 2 cosines used in the general solution for this domain?

    The domain is \(0\leq x < \infty\) and \(0\leq y\leq b\). \begin{align*} \phi(x, 0) &= f(x)\\ \phi(x, b) &= 0 \end{align*} I want to show that \[ \phi(x, y) = \frac{1}{\pi}\int_0^{\infty} \int_{-\infty}^{\infty}f(\xi) \frac{\sinh[u(b - y)]}{\sinh(ub)} \cos[u(\xi - x)]d\xi du \] Why isn't the...
  9. M

    Does the limit exist if the domain is restricted?

    In the case of a function like \sqrt{x}, where the function is only defined for values equal or greater than 0, does the limit exist at 0? I know both the left and right side limits as x approaches a must be equivalent and real for the limit at a to exist, but what if the domain is restricted...
  10. S

    A Question about the Domain and Range of a Function

    Homework Statement I constructed my own question to try to make sense of the following notation. g(x) = 2√x g : X → Y. What does X and Y equal? Homework Equations For 2√x, x = or > than 0. The Attempt at a Solution g(x) = 2√x g : [0, ∞) → [0, ∞) So X = Y = [0, ∞) The...
  11. F

    Confirming the domain for this integral

    Homework Statement In a Probabilities question it was known that 0<=x<=y<=1. It was asked what is the P(X+Y>1). So I had to find the domain for that integral first. Homework Equations The Attempt at a Solution I started with a graph sketch for 0<x<y<1 which gave half of the 1X1 square...
  12. D

    MHB Infinite domain to finite plate by a change of variables

    Consider the following solution to the steady state heat diffusion problem on an infinite y domain. \[ T(x, y) = \sum_{n = 1}^{\infty}c_n\exp\left(-\frac{\pi n}{\ell} y\right) \sin\left(\frac{\pi...
  13. P

    Understanding "S" in the Frequency Domain

    Can somebody tell me exactly what is 'S' in frequency domain? I know that s=σ+jw where σ is neper frequency and jw is complex frequency but i want the precise information on s you can suggest me a book in which it is clearly explained. Thank you.
  14. H

    Domain of Sturm-Liouville operators

    Hello, folks, A Sturm-Liouville operator is typically defined not on the whole space of C^2 functions, but rather on some subspace described by boundary conditions. My question is: are those subspaces closed (hence complete, hence Hilbert) in L^2? In case of an affirmative answer, how can...
  15. Y

    Evaluate complex value and domain of analytic function

    Homework Statement Can anyone help me to check whether the first two are correct or not? For the third question, i may need some help on it. Evaluate the following if they exist: a) sin(3Logi) b) (1+i)^(1/3-i) (principal value) Determine the largest open set in which the function...
  16. K

    MHB Solving the Domain: sqrt(x^2+y^2-1)>0 and 1<= x^2+y^2 <=20

    Im trying to combine this domain into something of the form a>b and b<c however I cannot seem to convert this equation :/ Is it possible to convert this domain into a single expression?? The domain is sqrt(x^2+y^2-1)>0 and 1<= x^2+y^2 <= 20 any ideas?? I've encountered this problem many...
  17. C

    Express current in time and frequency domain (capacitor)

    Homework Statement Calculate the current in the capacitor shown if the voltage input is a. v1(t) = 10cos(377t - 30°)V b. v2(t) = 12sin(377t + 60°)V Give answers in both time and frequency domain. Homework Equations I = dQ/dt = C * dV/dt The...
  18. I

    Integral on domain equals minus integral on the reverse domain?

    Homework Statement Why integral from a to b of f(x) equals "minus (-)" integral from b to a of f(x)? when a<b or a>b Homework Equations The Attempt at a Solution
  19. dexterdev

    Summation of random sequences and convolution in pdf domain?

    Hi all, I have an all time doubt here. We know that if r.v z = x + y where x and y are 2 random sequences having corresponding pdfs p(x) and p(y), the pdf of z, p(z) = convolution ( p(x),p(y) ). I have seen the derivation for the continuous case although not thorough how to prove it. I...
  20. Z

    Engineering Finding the Transfer Function of an RC Circuit in the Laplace domain

    Hi, Basically I have circuit with an input Vi (s) across a capacitor C which is in parallel with a resistor R1. And these 2 components are in series with another resistor R2 (please see attached drawing). The question states: Show that the transfer function of the circuit is: Vo/Vi...
  21. C

    Relation between entropys of spatial and frequency domain

    Dears, I wish to measure the entropy of visual data such as image and video. I did transform these image and videos into frequency domain such as DCT, then measured the entropy with these pdfs for each AC components of image and videos. However, when I measured the entropy over spatial domain...
  22. D

    Time domain noise from spectral density

    Hello. Say I have a given noise spectral density and I want to plot the random noise signal arising from this spectral density in the time domain. How can I generally accomplish this? For white noise, I would just pull numbers from a normal distribution, but I don't know what to do for non-white...
  23. N

    Domain of f(x) for √[(2x+1)/x3-3x2+2x]: Homework Solution and Explanation

    Homework Statement f(x)= √[(2x+1)/x3-3x2+2x] Homework Equations The Attempt at a Solution here For f(x) to exist x3-3x2+2x >0 and 2x+1≥0 by solving this i found that x \in [-\frac{1}{2},-∞]\bigcup[2,∞] but the answer given is (-∞,-1/2]\bigcup(0,1)(2,∞) so please...
  24. R

    Putting videos into the public domain

    Dear Experts If I invented something and took a video explaining it and include the date and time, and upload the video into the internet, what happens to the patentability of this idea or product or invention? Is there any benefit for doing so ? Thank you for reading. Have a nice...
  25. M

    MHB Find the domain of the function.

    Find the domain of the real valued function: f(x)=x−10−−−−−√x2+9x+8=x−10−−−−−√(x+8)(x+1) Why does the x2+9x+8 become (x+8)(x+1)? Thanks for the help!
  26. A

    MHB Product of polynomials over non-integral domain is 0

    Let n belongs to N, let p be a prime number and let Z/p^n Zdenote the ring of integers modulo p^n under addition and multiplication modulo p^n .Consider two polynomials f(x) = a_0 + a_1 x + a_2 x^2 +...a_n x^n and g(x)=b_0 + b_1 x + b_2 x^2 +...b_m x^m,given the coefficients are in Z/p^nZ...
  27. B

    MTech fresher in electronics domain

    I'm an MTech fresher in electronics domain, have been looking for job since 3 months.. its getting almost an year since i finished my exams. I don't even remember the names of companies where I'm applying and almost nil response. I did my BE from an average college and in mass recruitments i...
  28. M

    What is time domain aliasing in linear convolution?

    please anyone can help me to get the answer?I have idea about aliasing which is basically in frequency domain caused by lower sampling rate which does not satisfy the Nyquist criteria. Frequency aliasing refers to higher frequency getting the image of lower frequency.But what is time domain...
  29. Math Amateur

    MHB Unique Factorization Domain? Nature of Q_Z[x] - 2

    Let \mathbb{Q}_\mathbb{Z}[x] denote the set of polynomials with rational coefficients and integer constant terms. Prove that the only two units in \mathbb{Q}_\mathbb{Z}[x] are 1 and -1. Help with this exercise would be appreciated. My initial thoughts on this exercise are as follows: 1 and...
  30. Math Amateur

    MHB Unique Factorization Domain? Nature of Q_Z[x] - 1

    Unique Factorization Domain? Nature of Q_Z[x] Let \mathbb{Q}_\mathbb{Z}[x] denote the set of polynomials with rational coefficients and integer constant terms. (a) If p is prime in \mathbb{Z} , prove that the constant polynomial p is irreducible in \mathbb{Q}_\mathbb{Z}[x]. (b) If p and q...
  31. N

    Parametrizing a Triangle in 3D Space: What is the Domain of r(u,v)?

    Homework Statement A triangle is defined by the 3 points P=(1,0,0), Q=(0,2,0) and R=(0,0,2). Set up the double integral over its area. The Attempt at a Solution The triangle can be described as a plane 2x+y+z+2=0, with xE [0,1], yE [0,2], zE [0,2]. I parametrized it into r(u,v)...
  32. T

    Evaluate the integral with C be the boundary of the domain

    Homework Statement Let C be the boundary of the domain enclosed between y = x^2 and y = x. Assuming C is oriented counterclockwise. Evaluate the integral ∫c (6xy+e^(-x^2))dx Homework Equations I was thinking of using Green's Theorem. Would be the approach be correct? The Attempt at a...
  33. B

    MHB Find the constants given the domain and range

    Suppose you have a function y = f(x) such that the domain of f(x) is 1 ≤ x ≤ 6 and the range of f(x) is −3 ≤ y ≤ 5. a) Find constants B and C so that the domain of f(B(x − C)) is 8 ≤ x ≤ 9 B= C= b) Find constants A and D so that the range of Af(x) + D is 0 ≤ y ≤ 1 A= D= I'm working on...
  34. W

    Proof that a function is continuous on its domain

    Homework Statement We have f(x) = \frac{x^{2}+x-2}{x-1}+cos(x) , x\in\mathbb{R}\setminus \{1\} and wish to prove that it is continuous on its domain. Homework Equations The delta-epsilon definition of the continuity of a function. The Attempt at a Solution I've managed to reduce |f(x) -...
  35. A

    Thevenin equivalent phasor domain dependent voltage source

    Homework Statement determine thevenin equivalent of circuit at terminals (a,b): Homework Equations Z(L)=jwL Z(C)=-j/wC V(th)=V(oc) R(th)=V(ex)/I(ex) The Attempt at a Solution actually 1st i need help with finding V(th). i do know that V(th) would be the voltage across the 2ohm resistor, so...
  36. A

    Engineering Find thevenin circuit/ phasor domain

    Homework Statement obtain a thevenin equivalent circuit given that iS(t)=3cos(4x10^4)t A. to that end: a) transform the circuit to the phasor domain. b) apply source-transformation technique to obtain the thevenin equivalent circuit at terminals (a,b). c) transform the phasor-domain thevenin...
  37. N

    Finding the domain of this function

    Homework Statement Find the domain of 1/(sqrt(2x)-1)2 Note: the minus one is not included under the square root Homework Equations Title The Attempt at a Solution So the denominator cannot be zero so that means that sqrt(2x) cannot equal 1 x cannot be 1/2 letting the...
  38. J

    Need a cool function with this domain:

    So I made a program that, so far, converts a password to a string of the binary representation of its successive ASII characters. Here's some output for an example: "gs0dpsrln2" --------> 01100111011100110011000001100100011100000111001101110010011011000110111000110010 "8zoxdsjt9y" -------->...
  39. ThomasMagnus

    Combining functions and Domain

    Homework Statement F(x)=√x G(x)= 2/(x-4) Find g(f(x)) and its domain Homework Equations The Attempt at a Solution I am having trouble finding the domain for this composition. I know that g(f(x))= 2/(√x)-4 I believe that for the domain you combine the domain of the input (f(x)) and the...
  40. R

    Showing elements of a Principal Ideal Domain are Relatively Prime?

    Homework Statement Let ##R## be a PID and let ##\pi\in{R}## be an irreducible element. If ##B\in{R}## and ##\pi\not{|}B##, prove ##\pi## and ##B## are relatively prime. Homework Equations ##\pi## being irreducible means for any ##a,b\in{R}## such that ##ab=\pi##, one of #a# and #b# must be a...
  41. T

    Definition issue frequency domain - Random Signal Processing

    Hello i have a question about Random Signal Processing and the frequency domain. If i understand correctly one cannot use the Fourier transform to represent a stochastic process in the frequency domain. What is therefore used is the Power Spectral Density: S_X(f)=F\{R_X(\tau)\} Were F...
  42. C

    Triple integral problem - domain is that part of a cube btween 2 plane

    Homework Statement Evaluate the triple integral for the function \int\int\int y dV over that part of the cube 0 \leq x,y,z \leq 1 lying above the plane y +z = 1 and below the plane x+y+z = 2 Homework Equations The Attempt at a Solution This is the first attempt at a triple...
  43. bayan

    Limit & Domain Homework: Find Solution

    Homework Statement Find the limit (if it exists) and domain of the following function. (I do not need to use epsilon delta proof, just results on different curves to prove this) \stackrel{lim}{_{(x,y)→(−1,0)}} \frac {x(x+1)y^2}{(x+1)^2+y^2} Homework Equations The Attempt at a SolutionJust...
  44. M

    The domain on which a function is continuous

    Homework Statement Determine domain on which the following function is continuous f(x,y)= \left\{\begin{array}{cc} \frac{x(x+1)y^{2}}{(x+1)^{2}+y^{2}} & (x,y)\neq(-1,0)\\ 1 & (x,y)=(-1,0) \end{array}\right. Homework Equations The Attempt at a Solution Because the numerator...
  45. G

    Solving the Wave Equation in semi-infinite domain with easy ICs

    Hi, so the problem is this: I am trying to solve (analytically) the wave equation with c=1: u_{xx}=u_{tt} on x,t>0 given the initial conditions u(x,0)=u_{t}(x,0)=0, u(0,t)=sin(wt) I know how to solve on semi-infinite domains for quite a few cases using Green's Functions, Fourier Transforms...
  46. F

    Setting Up the Domain for Maxima/Minima Word Problems

    Good day everyone. I'm confused about how I SHOULD set up the domain of my function that models the word problem. Suppose I have a word problem that goes like this: A square box with no top is to be made by cutting congruent squares from the four corners of a square metal sheet and then...
  47. I

    Volume of linear transformations of Jordan domain

    Homework Statement Let T:\mathbb{R}^n\rightarrow\mathbb{R}^n be a linear transformation and R\in \mathbb{R}^n be a rectangle. Prove: (1) Let e_1,...,e_n be the standard basis vectors of \mathbb{R}^n (i.e. the columns of the identity matrix). A permutation matrix A is a...
  48. I

    MHB Volume of linear transformation of Jordan domain

    Let $T:\mathbb{R}^n\rightarrow\mathbb{R}^n$ be a linear transformation and $R\in \mathbb{R}^n$ be a rectangle. Prove: (1) Let $e_1,...,e_n$ be the standard basis vectors of $\mathbb{R}^n$ (i.e. the columns of the identity matrix). A permutation matrix $A$ is a matrix whose columns are...
  49. A

    Domain and Range of this function

    Homework Statement What is the domain and range of the function y = \frac{2}{x^2-4} The Attempt at a Solution I'm lost, and I noticed it seems like a difference of squares so what I did is y = \frac{2}{(x-2)(x+2)}. So the x value of vertex is 0. And i subbed this into the equation...
  50. Fernando Revilla

    MHB Mr.Ask's question at Yahoo Answers (Two variables, domain and range)

    Here is the question: Here is a link to the question: Find the range and domain of function of 2 varibles:? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
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