Linear Definition and 1000 Threads

  1. karush

    MHB 10) AP Calculus linear functions

    $\textbf{10)} \\ f(x)\text{ is continuous at all } \textit{x} \\ \displaystyle f(0)=2, \, f'(0)=-3,\, f''(0)=0 $ $\text{let} \textbf{ g } \text{be a function whose derivative is given by}\\ \displaystyle g'(x)=e^{-2 x} (3f(x))+2f'(x) \text{ for all x}\\$ $\text{a) write an equation of the...
  2. L

    I 2° order linear, homogeneous, variable coefficients

    sin(x) * y''(x) + 2cos(x) * y(x) = 0 y(0) = 0 y'(0) = 1 how do I solve it? (I know the solution because I have created the diff. equation starting from a simple function). -- lightarrow
  3. thecourtholio

    Energy for Linear 1D Systems - 1D potential

    Homework Statement A particle of mass m moves along the x–axis under the influence of force ##F_x=-ax+bx^3## , where a and b are known positive constants. (a) Find, and sketch, the particle's potential energy, taking U(0) = 0 (b) Identify and classify all equilibrium points (c) Find the...
  4. K

    Proving That Any Vector in a Vector Space V Can Be Written as a Linear Combination of a Basis Set

    Homework Statement Show that any vector in a vector space V can be written as a linear combination of a basis set for that same space V. Homework Equations http://linear.ups.edu/html/section-VS.html We are suppose to use the 10 rules in the above link, plus the fact that if you have a lineraly...
  5. S

    Angular Velocity in Linear Momentum Equation

    m1v1 = m2v2 v = rω m1(rω)1 = m2(rω)2 m1ω1 = m2ω2 Does this make sense?
  6. M

    How Do You Calculate Change in Kinetic Energy and Momentum for a Turning Loader?

    Homework Statement A 15 000kg loader traveling east at 20km/h turns south and travels at 25km/h. Calculate the change in the loader's a) kinetic energy b) linear momentum Homework Equations ΔKE= 1/2mvf^2 –1/2mvi^2 Δp= mv2 –mv1 m= 15000 vi = 20km/h = 5.56m/s vf= 25km/h = 6.94m/s The Attempt at...
  7. M

    I Linear least-squares method and row multiplication of matrix

    Suppose that I have an overdetermined equation system in matrix form: Ax = b Where x and b are column vectors, and A has the same number of rows as b, and x has less rows than both. The least-squares method could be used here to obtain the best possible approximative solution. Let's call this...
  8. mmcsa

    Determining linear velocity of pendulum

    Hello, I'm trying to develop a pendulum to test protective equipment so I want to work out the length I'll need to generate a desired velocity and the necessary mass I'll need for a specific moment of inertia. I know there are multiple ways to solve for linear velocity with equating Ek and Ep...
  9. A

    Linear differential equation hwk check

    1. Homework Statement Posted Homework Equations Posted The Attempt at a Solution Posted I just need the work to be checked.
  10. kyphysics

    Linear Algebra Any Great Linear Algebra Books for First-Time Learners?

    What are the best ones and why for a first-timer like myself (doing self-study)? Thanks very much everyone.
  11. R

    MHB Proving disjoint of Kernel and Image of a linear mapping

    I am working on a problem that goes like this: Show that $Ker (F) \cap I am (F) = \{0\}$ if $F: W \rightarrow W$ is linear and if $F^4 = F.$ I have the solution but there is one step which I need help: (the delineation is mine) (1) Suppose that there exists $x$, such that $x \in Ker(F) \cap...
  12. T

    Linear polarized microstrip patch antenna - design help

    hi there,im pretty new to antenna design, still have a lot of theory to go through, so please be kind. ;)I have to design a linearly polarized microstrip patch antenna (rectangular) that is fed with 2 coaxial probe feeds. The patch should be a square (L=W), so i can place 2 feeds orthogonally...
  13. M

    I Expanding linear independent vectors

    Hi PF! The other day in class my professor mentioned something about expanding linear independent vectors, but he did not elaborate. From what I understand, if ##x_1,...,x_k## are linearly independent vectors in ##V##, where ##dimV=n>k##, how would you extend ##x_1,...x_k## to a basis ##\{...
  14. M

    Linear transformations, images for continuous functions

    Homework Statement Let ##C## be the space of continuous real functions on ##[0,\pi]##. With any function ##f\in C##, associate another function ##g=T(f)## defined by $$g=T(f)\equiv \int_0^\pi \cos(t-\tau) f(\tau) \, d \tau$$ a) Show ##T## is a linear transformation from ##C## to ##C##. b)What...
  15. P

    Is the system linear or nonlinear

    Homework Statement 3y(t)+2=x(t) Homework Equations k1y1(t) + k2y2(t) + 2(k1+k2) = k1x1(t)+k2x2(t) The Attempt at a Solution I know the system is non linear but I cannot explain why. It has something to do with 2(k1+k2) but I am unsure.
  16. R

    Quick question on intro to linear algebra book

    I'm looking at purchasing Algebra (2nd Edition) by Michael Artin, is this a good book to purchase as my first intro to linear algebra book for self learning?
  17. J

    MHB Two problems: linear distance and directed graph

    1.) Two volumes of an encyclopedia stand side by side, in order, on a shelf. A bookworm starts at page i of Volume I and bores its way in a straight line to the last page of Volume II. Each cover is 1 mm thick, and the first volume is 2/5 as thick as the second volume. The first volume is 40 mm...
  18. J

    Help finding general solution for 2nd order linear DE

    Homework Statement Find the general solution for the DE: t2y''-2y=0 Homework Equations These were given for other parts of the problem so I'm not sure if they're relevant. y1(t)=t2, y2(t)=t-1, y(1)=-2, y'(1)=-7 The Attempt at a Solution The t2 at the front was really stumping me and I'm not...
  19. Christopher117C

    Centripetal Force of a linear spring

    I was given a question relating centripetal force to solve A linear spring of negligible mass requires a force of 18.0 N to cause its length to increase by 1.0 cm. A sphere of mass 75.0 g is attached to one end of the spring. The distance between the centre of the sphere M and the other end P of...
  20. almarpa

    Algebra Similar book to Kleppner's Quick Caculus for linear algebra

    So anyone of you know a book that provides a gentle and quick refresher for linear algera, in the spirit of the book "Quick Calculus" by Kleppner and Ramsey? Now that I am studying quantum mechanics, I feel I need to review the linear algebra I studied during my engineering degree. Thanks.
  21. ShaiNaveh

    What is the formula for calculating force in a crank and slider mechanism?

    Hi all, I have a question regarding a simple crank and slider mechanism, but I'm not a mathematician. This means that long formulas scare me... (: I've been searching around and haven't found anything I can really understand. I'm trying to get a "ball park" formula to calculate the amount of...
  22. binbagsss

    QM Bra & Ket Linear Algebra Hermitian operator proof -- quick question

    Homework Statement Hi, Just watching Susskind's quantum mechanics lecture notes, I have a couple of questions from his third lecture: Homework Equations [/B] 1) At 25:20 he says that ## <A|\hat{H}|A>=<A|\hat{H}|A>^*## [1] ##<=>## ##<B|\hat{H}|A>=<A|\hat{H}|B>^*=## [2] where ##A## and ##B##...
  23. RJLiberator

    Semi-circle linear charge Electric Field

    Homework Statement A semi-circle of radius R has a charge Q uniformly distributed over its length, which provides a line charge density λ. Determine E at the origin. Homework EquationsThe Attempt at a Solution https://www.physicsforums.com/attachments/105239 I can tell by argument of...
  24. B

    MHB Finding the Measures of Angles in a Linear Pair

    <1 and <2 form a linear pair. If m<1 = 5x + 9 and m<2 = 3x + 11, find the measures of both angles.
  25. a_c_e

    Gas Spring and Linear Actuator calculation....

    May I start by saying hello to all and that I have visited the site before, but have yet to create an account until now. With that said, I am having difficulty calculating proper numbers for a project I am designing. Mind you, it has been about seven years since I was in any physics or...
  26. T

    Linear Algebra, subset of R2 not closed under scalar multipl

    Homework Statement Construct a subset of the x-y plane R2 that is (a) closed under vector addition and subtraction, but not scalar multiplication. Hint: Starting with u and v, add and subtract for (a). Try cu and cv Homework Equations vector addition, subtraction and multiplication The...
  27. tomwilliam2

    I Solving linear differential equations

    I have the following linear differential equations: ##A\dot{x} + By = 0## ##C\dot{y} + Dx = 0## Where x and y are functions of t, and A through D are constants. I can solve this fairly easily by differentiating the first equation, rearranging, and removing one of the variables, which gives me a...
  28. T

    How can I modify a LM337 circuit to increase current output?

    So many moons ago I made myself a pretty bog standard dual linear bench power supply using an LM317 and LM337 to give me -15 - 0 - +15. In an attempt to get more current out of it (for no real reason other than because I can) I got a larger transformer and a beefier rectifier, then using the...
  29. D

    Linear Algebra with Proof by Contradiction

    This is a linear algebra question which I am confused. 1. Homework Statement Prove that "if the union of two subspaces of ##V## is a subspace of ##V##, then one of the subspaces is contained in the other". The Attempt at a Solution Suppose ##U##, ##W## are subspaces of ##V##. ##U \cup W##...
  30. M

    Wrong answer on Linear Algebra and Its Applications 4th Ed.

    Homework Statement The Attempt at a Solution \left[ \begin{array}{cccc} 1 & 0 & 5 & 2 \\ -2 & 1 & -6 & -1 \\ 0 & 2 & 8 & 6 \end{array} \right] \sim \left[ \begin{array}{cccc} 1 & 0 & 5 & 2 \\ 0 & 1 & 4 & 3 \\ 0 & 0 & 0 & 0 \end{array} \right] From the RREF it is...
  31. F

    Expectation values linear harmonic oscillator

    hello :-) here is my problem...: 1. Homework Statement For a linear harmonic oscillator, \hat{H} = \frac{\hat{p}^2}{2m} + \frac{1}{2} m \omega^2x^2 a) show that the expectation values for position, \bar{x}, and momentum \bar{p} oscillate around zero with angular frequency \omega. Hint...
  32. T

    Linear Algebra, forcing a row exchange.

    the answer key said d is supposed to be 10. but there's a way to evade that row exchange. 1st picture is the question and the 2nd picture is the elimination steps.
  33. shintashi

    For gear teeth to linear shaft, what's the center point?

    I used to know this back when i worked with Flash animation, but I'm working on a 3D printer now and I've forgotten, when you have a set of teeth, on a linear shaft and a gear, do you base the unrolling of the gear, for the spacing, on the inside of the teeth, the outside of the teeth, or the...
  34. D

    I Linear equations and superposition of wavefunctions

    Hi. I have read many times that the Schrodinger equation is a linear equation and so if Ψ1 and Ψ2 are both solutions to the equation then so is Ψ1 + Ψ2. Is this use of the word linear the same as generally used for differential equations ? As the Schrodinger equation is also an eigenvalue...
  35. M

    A What Is the Spectrum of a Linear Operator in L2 Spaces?

    http://<img src="https://latex.codecogs.com/gif.latex?L_{2}[0,1]->L_{2}[0,1]\int_{0}^{1}\left&space;|t-s&space;\right&space;|f(s)ds" title="L_{2}[0,1]->L_{2}[0,1]\int_{0}^{1}\left |t-s \right |f(s)ds" />[/PLAIN] I have many doubts on linear operator. How I can find a spectrum of a linear...
  36. M

    Calculating Linear Combinations of Vectors: Step-by-Step Guide

    Homework Statement Consider the four vectors (1, 1, 1), (2, −1, 3), (1, 7, −1) and (1, 4, 0). Calculate how many ways you can write (1, 1, 1) as a linear combination of the other three, explaining your reasoning. The Attempt at a Solution wouldn't any of these combinations give the correct...
  37. C

    Linear application and différential

    Homework Statement Let be E a normded vectoriel space, ##dim(E) = m \in \mathbb{N}^{*}##, I have to show that ##\exists \rho_{1}, \rho_{2} > 0 | \forall u \in L(E), ||u^{m} - Id| \leq \rho_{1} \Rightarrow |u - Id| \leq \rho_{2}##. Homework Equations Nothing. The Attempt at a Solution [/B] I...
  38. H

    A Identical Fermions in identical linear combinations

    According to Pauli principle the two fermions can not occupy one state of a Hamiltonian. Can the two fermions occupy a state which is linear recombination of two states of the Hamiltonian?
  39. H

    B What Function Models Linear Amplitude Decay?

    I collected data on a periodic mechanical motion. The amplitude is damped linearly. What mathematical function models linear amplitude decay. All I can find is exponential decay of a sine wave.
  40. icesalmon

    Independent study for linear algebra

    Hello, I just completed a first course in linear algebra and really enjoyed my studies. So much so that I want to pursue it more in the fall as an independent study, i am a EE major in college and was curious what directions might be useful for applications in that field.
  41. Z

    How to derive linear velocity from position and angular vel.ocity

    Hello! I'm trying to derive the linear velocity vector from the position vector and the angular momentum vector. I've seen on the internet that V = W x R (V,W and R are all vectors and x is the cross product) but I cannot for the life of me derive it! I've tried doing it by writing out the...
  42. T

    Partial Derivatives and the Linear Wave Equation

    Homework Statement I'm reading through the derivations of the linear wave equation. I'm following everything, except the passage I highlighted in yellow in the below attachment: Homework Equations I'm not understanding why partials must be used because "we evaluate this tangent at a...
  43. J

    I Video that show how a linear accelerator was built in 1967

    Hi folks, I have just found a video on youtube that shows how a 2 mile linear accelerator was built in 1967, I share it with you, hopefully you will enjoy it as much as I did:
  44. B

    I A Question about Notation and Continuous Linear Functionals

    I have reading through various sources on linear functionals, but all seem somewhat inconsistent with regard to denoting the set of all linear functionals and the set Also, what is the standard definition of a continuous linear functional? I really couldn't find much besides this Let ##f : V...
  45. marsupial

    Calculate linear acceleration of a pivoted stick

    Homework Statement A uniform thin stick of mass M and length L has a moment of inertia about its centre of mass of I = (1/12)ML^2. The stick, which is pivoted at one end, is held horizontal and then released. Assuming the pivot is frictionless, calculate: i) the linear acceleration of the free...
  46. E

    I If you were to perform a linear regression of log10(B) vs log10(x)....

    If you were to perform a linear regression of log10(B) vs log10(x) what would you expect the slope to be? The expected relationship between B and x is B(x) = μoI(2πx)-1
  47. Auburn2017

    How Do You Solve Nonuniform Linear Acceleration Problems?

    Homework Statement Refer to figure. Homework Equations v=ds/dt → ds=vdt a=dv/dt → dv=adt ads=vdv The Attempt at a Solution I tried taking the derivative of the given position function. Then I am kind of lost from there.
  48. R

    I Dividing quadratic with linear

    I have two table, first one changes quadratically and second table changes linearly. 46 ... 55 90 ... 57 142 ... 59 202 ... 61 270 ... 63 346 ... 65 430 ... 67 522 ... 69 622 ... 71 730 ... 73 846 ... 75 970 ... 77 and so...
  49. D

    Linear Transformation R4 to R4: KerT + ImT = R4

    Homework Statement Let T be a Linear Transformation defined on R4 ---> R4 Is that true that the following is always true ? KerT + ImT = R4Homework EquationsThe Attempt at a Solution Since every vector in R4 must be either in KerT or the ImT, so the addition of those subspace contains R. and ofc...
  50. Mrq

    Admissions Solving Quadratic Equations with a Linear Polynomial Relation

    I derived a relation between the product of two linear polynomials and the square of their average. It can be used to solve any quadratic equation. Will this help me getting into a top university?
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