DOCSLIB.ORG

The Original Euler's Calculus-Of-Variations Method: Key

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Original Euler's Calculus-Of-Variations Method: Key 1 1 The original Euler’s calculus-of-variations method: 2 Key to Lagrangian mechanics for beginners 3 Jozef Hanca) 4 Technical University, Vysokoskolska 4, 042 00 Kosice, Slovakia 5 ABSTRACT 6 Leonhard Euler's original version of the calculus of variations was geometric and easily visualized. Euler (1707- 7 1783) abandoned his version because of the absence in his day of the exact definition of a limit, adopting instead 8 the algebraic method of Lagrange. Lagrange’s elegant technique not only bypassed the need for intuition about 9 passage to the limit in calculus but also eliminated Euler’s geometrical insight. More recently, Euler's method 10 has been resurrected, shown to be rigorous and more general than Lagrange's, and employed in computer 11 solutions of physical processes. In our classrooms the study of advanced mechanics is still dominated by 12 Lagrange's method, which students often apply uncritically using "variational recipes". We describe an 13 adaptation of Euler's method that restores intuition and geometric visualization and has applications in almost all 14 of undergraduate physics, especially modern physics. Finally, we present Euler's method as a natural 15 introduction to computer-executed numerical analysis of boundary value problems and the finite element 16 method. 17 18 I. INTRODUCTION 19 In his pioneering 1744 work The method of finding plane curves that show some property of 20 maximum and minimum,1 Leonhard Euler introduced a general mathematical procedure or 21 method for the systematic investigation of variational problems. Along the way he formulated 22 the variational principle for mechanics, his version of the principle of least action.2 23 Mathematicians consider this event to be the beginning of one of the most important branches 24 of mathematics, the calculus of variations. Physicists also regard it as the first variational 25 treatment of mechanics, which later contributed significantly to analytic mechanics and 26 ultimately to the fundamental underpinnings of twentieth-century physics: general relativity 27 and quantum mechanics. 28 It is not certain3 when Euler first became seriously interested in variational problems and 29 properties. We know that he was influenced by Newton and Leibniz, but primarily by James 30 and Johann Bernoulli who were also attracted to the subject. The best known examples of 31 variational calculus include Fermat’s principle of least time ("between fixed endpoints, light 32 takes the path for which the travel time is shortest"), Bernoulli’s brachistochrone problem4 33 ("find a plane curve between two points along which a particle descends in the shortest time 34 under the influence of gravity"), and the so-called isoperimetric problem ("find the curve 35 which encloses the greatest area for a given perimeter"). 36 While each of Euler's contemporaries devised a special method of solution depending on the 37 character of the particular variational problem, Euler's own approach was purely mathematical 38 and therefore much more general. Employing geometrical considerations and his phenomenal 39 intuition for the limit-taking process of calculus, Euler established a method that allows us to 40 solve problems using only elementary calculus. 41 In 1755, the 19-year-old Joseph-Louis Lagrange wrote Euler a brief letter to which he 42 attached a mathematical appendix with a revolutionary technique of variations. Euler 43 immediately dropped his method, espoused that of Lagrange, and renamed the subject the 44 calculus of variations.5 Lagrange’s elegant techniques eliminated from Euler’s methods not 45 only the need for intuition about passage to the limit in calculus but also Euler’s geometrical 46 insight. It reduced the entire process to a quite general analytical manipulation which to this 2 1 day characterizes the calculus of variations. Since in Euler’s time the exact proof of the 2 passage to the limit could not be carried out,6 his method fell into disuse. 3 However, at the beginning of the twentieth century there was an interest in approximate 4 solutions of variational problems and partial differential equations. Euler’s method again 5 attracted the attention of mathematicians, and in the end the modern numerical analysis of 6 variational problems and differential equations7,8 fully vindicated Euler’s intuition. Euler’s 7 method rose like a phoenix and became one of the first direct variational methods.7 At 8 approximately the same time another direct methods were devised, the well-known Rayleigh- 9 Ritz method (1908) and its extension called Galerkin’s method (1915). Finally, all these 10 methods for solving differential equations led to the formulation of the very powerful Finite 11 Element Method (FEM) (1943, 1956)9,10 for carrying out accurate computer predictions of 12 physical processes. 13 For more than a century students in upper undergraduate classes in mechanics have been 14 taught to use Lagrange’s calculus of variations to derive the Lagrange equations of motion 15 from Hamilton’s principle, which is also known as the principle of least action (so renamed by 16 Landau and Feynman). However, there appears to be a conflict between the larger view of 17 theoretical physics and the pedagogy of upper level physics classes: (1) From the viewpoint of 18 modern theoretical physics, variational treatments such as the principle of least action with 19 Lagrangian formalism are "core technology” that can be extended to describe systems beyond 20 mechanics.11 (2) Because the calculus of variations is not widely taught in upper level physics 21 classes, students often meet it first in an advanced mechanics class, find the manipulations 22 daunting, do not develop a deep conceptual understanding of either the new (to them) 23 mathematics or the new physics, and end up memorizing "variational recipes." 24 Is there a strategy or method that allows us to introduce important variational treatments of 25 mechanics and physical laws as "core technology" while at the same time teaching students to 26 apply it with understanding and insight? 27 In the present paper we propose that Euler’s method be used as an introductory procedure 28 instead of the Lagrangian technique of variations. Section II is devoted to a detailed 29 description of Euler’s method from his 1744 work, together with notes for its pedagogic use. 30 We will see that Euler's method permits visualization useful for learning physics and requires 31 only elementary calculus. 32 In Sec. III we illustrate the computer application of Euler's method using interactive software 33 which allows students to carry out their own investigations of the principle of least action and 34 Lagrangian mechanics. Contemporary education research demonstrates that student-directed 35 exploration of a subject helps to develop genuine understanding of concepts and their 36 applications. 37 The final Sec. IV gives a list of other applications of the method which apply it to almost all 38 of undergraduate physics, especially modern physics. 39 40 II. BASIC IDEAS OF EULER’S METHOD 41 A. Euler’s original considerations 42 The exact transcription of original Euler’s derivations from his 1744 work is reproduced in 43 Goldstine’s book3. Several other mathematics and physics books offer somewhat modified 44 versions.12 Here we present only the essential considerations of the Euler approach.13 3 1 Euler’s starting point was his ingenious reduction of the variety of variational problems to a 2 single abstract mathematical form. He recognized that solving the variational problem means 3 finding an extremal (or more strictly stationary) value of a definite integral. 4 As a first example Euler presents a solution of the simplest variational problem: A function 5 F = F(x, y, y′) has three variables: the independent coordinate x, the dependent coordinate y, 6 and its derivative y′ with respect to the independent coordinate. Our problem is to determine a 7 the curve y = y(x), with 0 ≤ x ≤ a , which will make the definite integral ∫ F(x, y, y′)dx 0 8 extremal. Such an integral occurs in the brachistrochrone problem or in the description of 9 motion using the principle of least action. 10 Euler presents three crucial ideas which allowed him to solve the problem using only 11 elementary calculus: 12 (1) divide the interval between x = 0 and x = a into many small subintervals, each of width 13 ∆x ; 14 (2) replace the given integral by a sum ∑ F(x, y, y′)∆x . In each term of this sum evaluate 15 the function F at the initial point x, y of the corresponding subinterval and approximate the 16 derivative dy/dx by the slope of the straight line between initial and final points of the 17 subinterval; 18 (3) employ a visualized “geometrical” way of thinking. 19 Goldstine’s book3 displays (p.69) the original Euler’s figure (Fig. 1) in which the curve anz 20 represents the unknown extremal curve y = y(x): 21 22 23 Fig. 1. Original Euler’s figure used in his derivation 24 25 Figure 1 illustrates the fact that if we shift an arbitrarily chosen point on the curve, for 26 example point n, up or down by an increment nv, then in addition to the obvious change in the 27 ordinate yn of the point n, there are also changes in neighboring segments mn and no and their 28 slopes. All other points and slopes remain unchanged. These changes mean that only two 29 terms in the integral sum ∑ F(x, y, y′)∆x are affected, the first corresponding to segment mn 4 1 and the second to segment no. We can also say the variation of yn causes the integral sum to 2 be a function of single variable yn .
Load more

Recommended publications
  • Chapter 4 Finite Difference Gradient Information
    Chapter 4 Finite Difference Gradient Information In the masters thesis Thoresson (2003), the feasibility of using gradient- based approximation methods for the optimisation of the spring and damper characteristics of an off-road vehicle, for both ride comfort and handling, was investigated. The Sequential Quadratic Programming (SQP) algorithm and the locally developed Dynamic-Q method were the two successive approximation methods used for the optimisation. The determination of the objective function value is performed using computationally expensive numerical simulations that exhibit severe inherent numerical noise. The use of forward finite differences and central finite differences for the determination of the gradients of the objective function within Dynamic-Q is also investigated. The results of this study, presented here, proved that the use of central finite differencing for gradient information improved the optimisation convergence history, and helped to reduce the difficulties associated with noise in the objective and constraint functions. This chapter presents the feasibility investigation of using gradient-based successive approximation methods to overcome the problems of poor gradient information due to severe numerical noise. The two approximation methods applied here are the locally developed Dynamic-Q optimisation algorithm of Snyman and Hay (2002) and the well known Sequential Quadratic 47 CHAPTER 4. FINITE DIFFERENCE GRADIENT INFORMATION 48 Programming (SQP) algorithm, the MATLAB implementation being used for this research (Mathworks 2000b). This chapter aims to provide the reader with more information regarding the Dynamic-Q successive approximation algorithm, that may be used as an alternative to the more established SQP method. Both algorithms are evaluated for effectiveness and efficiency in determining optimal spring and damper characteristics for both ride comfort and handling of a vehicle.
    [Show full text]
  • Introduction to Differential Equations
    Introduction to Differential Equations Lecture notes for MATH 2351/2352 Jeffrey R. Chasnov k kK m m x1 x2 The Hong Kong University of Science and Technology The Hong Kong University of Science and Technology Department of Mathematics Clear Water Bay, Kowloon Hong Kong Copyright ○c 2009–2016 by Jeffrey Robert Chasnov This work is licensed under the Creative Commons Attribution 3.0 Hong Kong License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/hk/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. Preface What follows are my lecture notes for a first course in differential equations, taught at the Hong Kong University of Science and Technology. Included in these notes are links to short tutorial videos posted on YouTube. Much of the material of Chapters 2-6 and 8 has been adapted from the widely used textbook “Elementary differential equations and boundary value problems” by Boyce & DiPrima (John Wiley & Sons, Inc., Seventh Edition, ○c 2001). Many of the examples presented in these notes may be found in this book. The material of Chapter 7 is adapted from the textbook “Nonlinear dynamics and chaos” by Steven H. Strogatz (Perseus Publishing, ○c 1994). All web surfers are welcome to download these notes, watch the YouTube videos, and to use the notes and videos freely for teaching and learning. An associated free review book with links to YouTube videos is also available from the ebook publisher bookboon.com. I welcome any comments, suggestions or corrections sent by email to [email protected].
    [Show full text]
  • 3 Runge-Kutta Methods
    3 Runge-Kutta Methods In contrast to the multistep methods of the previous section, Runge-Kutta methods are single-step methods — however, with multiple stages per step. They are motivated by the dependence of the Taylor methods on the specific IVP. These new methods do not require derivatives of the right-hand side function f in the code, and are therefore general-purpose initial value problem solvers. Runge-Kutta methods are among the most popular ODE solvers. They were first studied by Carle Runge and Martin Kutta around 1900. Modern developments are mostly due to John Butcher in the 1960s. 3.1 Second-Order Runge-Kutta Methods As always we consider the general first-order ODE system y0(t) = f(t, y(t)). (42) Since we want to construct a second-order method, we start with the Taylor expansion h2 y(t + h) = y(t) + hy0(t) + y00(t) + O(h3). 2 The first derivative can be replaced by the right-hand side of the differential equation (42), and the second derivative is obtained by differentiating (42), i.e., 00 0 y (t) = f t(t, y) + f y(t, y)y (t) = f t(t, y) + f y(t, y)f(t, y), with Jacobian f y. We will from now on neglect the dependence of y on t when it appears as an argument to f. Therefore, the Taylor expansion becomes h2 y(t + h) = y(t) + hf(t, y) + [f (t, y) + f (t, y)f(t, y)] + O(h3) 2 t y h h = y(t) + f(t, y) + [f(t, y) + hf (t, y) + hf (t, y)f(t, y)] + O(h3(43)).
    [Show full text]
  • Runge-Kutta Scheme Takes the Form   K1 = Hf (Tn, Yn);  K2 = Hf (Tn + Αh, Yn + Βk1); (5.11)   Yn+1 = Yn + A1k1 + A2k2
    Approximate integral using the trapezium rule: h Y (t ) ≈ Y (t ) + [f (t ; Y (t )) + f (t ; Y (t ))] ; t = t + h: n+1 n 2 n n n+1 n+1 n+1 n Use Euler's method to approximate Y (tn+1) ≈ Y (tn) + hf (tn; Y (tn)) in trapezium rule: h Y (t ) ≈ Y (t ) + [f (t ; Y (t )) + f (t ; Y (t ) + hf (t ; Y (t )))] : n+1 n 2 n n n+1 n n n Hence the modified Euler's scheme 8 K1 = hf (tn; yn) > h <> y = y + [f (t ; y ) + f (t ; y + hf (t ; y ))] , K2 = hf (tn+1; yn + K1) n+1 n 2 n n n+1 n n n > K1 + K2 :> y = y + n+1 n 2 5.3.1 Modified Euler Method Numerical solution of Initial Value Problem: dY Z tn+1 = f (t; Y ) , Y (tn+1) = Y (tn) + f (t; Y (t)) dt: dt tn Use Euler's method to approximate Y (tn+1) ≈ Y (tn) + hf (tn; Y (tn)) in trapezium rule: h Y (t ) ≈ Y (t ) + [f (t ; Y (t )) + f (t ; Y (t ) + hf (t ; Y (t )))] : n+1 n 2 n n n+1 n n n Hence the modified Euler's scheme 8 K1 = hf (tn; yn) > h <> y = y + [f (t ; y ) + f (t ; y + hf (t ; y ))] , K2 = hf (tn+1; yn + K1) n+1 n 2 n n n+1 n n n > K1 + K2 :> y = y + n+1 n 2 5.3.1 Modified Euler Method Numerical solution of Initial Value Problem: dY Z tn+1 = f (t; Y ) , Y (tn+1) = Y (tn) + f (t; Y (t)) dt: dt tn Approximate integral using the trapezium rule: h Y (t ) ≈ Y (t ) + [f (t ; Y (t )) + f (t ; Y (t ))] ; t = t + h: n+1 n 2 n n n+1 n+1 n+1 n Hence the modified Euler's scheme 8 K1 = hf (tn; yn) > h <> y = y + [f (t ; y ) + f (t ; y + hf (t ; y ))] , K2 = hf (tn+1; yn + K1) n+1 n 2 n n n+1 n n n > K1 + K2 :> y = y + n+1 n 2 5.3.1 Modified Euler Method Numerical solution of Initial Value Problem: dY Z tn+1 =
    [Show full text]
  • The Original Euler's Calculus-Of-Variations Method: Key
    Submitted to EJP 1 Jozef Hanc, [email protected] The original Euler’s calculus-of-variations method: Key to Lagrangian mechanics for beginners Jozef Hanca) Technical University, Vysokoskolska 4, 042 00 Kosice, Slovakia Leonhard Euler's original version of the calculus of variations (1744) used elementary mathematics and was intuitive, geometric, and easily visualized. In 1755 Euler (1707-1783) abandoned his version and adopted instead the more rigorous and formal algebraic method of Lagrange. Lagrange’s elegant technique of variations not only bypassed the need for Euler’s intuitive use of a limit-taking process leading to the Euler-Lagrange equation but also eliminated Euler’s geometrical insight. More recently Euler's method has been resurrected, shown to be rigorous, and applied as one of the direct variational methods important in analysis and in computer solutions of physical processes. In our classrooms, however, the study of advanced mechanics is still dominated by Lagrange's analytic method, which students often apply uncritically using "variational recipes" because they have difficulty understanding it intuitively. The present paper describes an adaptation of Euler's method that restores intuition and geometric visualization. This adaptation can be used as an introductory variational treatment in almost all of undergraduate physics and is especially powerful in modern physics. Finally, we present Euler's method as a natural introduction to computer-executed numerical analysis of boundary value problems and the finite element method. I. INTRODUCTION In his pioneering 1744 work The method of finding plane curves that show some property of maximum and minimum,1 Leonhard Euler introduced a general mathematical procedure or method for the systematic investigation of variational problems.
    [Show full text]
  • Numerical Stability; Implicit Methods
    NUMERICAL STABILITY; IMPLICIT METHODS When solving the initial value problem 0 Y (x) = f (x; Y (x)); x0 ≤ x ≤ b Y (x0) = Y0 we know that small changes in the initial data Y0 will result in small changes in the solution of the differential equation. More precisely, consider the perturbed problem 0 Y"(x) = f (x; Y"(x)); x0 ≤ x ≤ b Y"(x0) = Y0 + " Then assuming f (x; z) and @f (x; z)=@z are continuous for x0 ≤ x ≤ b; −∞ < z < 1, we have max jY"(x) − Y (x)j ≤ c j"j x0≤x≤b for some constant c > 0. We would like our numerical methods to have a similar property. Consider the Euler method yn+1 = yn + hf (xn; yn) ; n = 0; 1;::: y0 = Y0 and then consider the perturbed problem " " " yn+1 = yn + hf (xn; yn ) ; n = 0; 1;::: " y0 = Y0 + " We can show the following: " max jyn − ynj ≤ cbj"j x0≤xn≤b for some constant cb > 0 and for all sufficiently small values of the stepsize h. This implies that Euler's method is stable, and in the same manner as was true for the original differential equation problem. The general idea of stability for a numerical method is essentially that given above for Eulers's method. There is a general theory for numerical methods for solving the initial value problem 0 Y (x) = f (x; Y (x)); x0 ≤ x ≤ b Y (x0) = Y0 If the truncation error in a numerical method has order 2 or greater, then the numerical method is stable if and only if it is a convergent numerical method.
    [Show full text]
  • Leonhard Euler: His Life, the Man, and His Works∗
    SIAM REVIEW c 2008 Walter Gautschi Vol. 50, No. 1, pp. 3–33 Leonhard Euler: His Life, the Man, and His Works∗ Walter Gautschi† Abstract. On the occasion of the 300th anniversary (on April 15, 2007) of Euler’s birth, an attempt is made to bring Euler’s genius to the attention of a broad segment of the educated public. The three stations of his life—Basel, St. Petersburg, andBerlin—are sketchedandthe principal works identified in more or less chronological order. To convey a flavor of his work andits impact on modernscience, a few of Euler’s memorable contributions are selected anddiscussedinmore detail. Remarks on Euler’s personality, intellect, andcraftsmanship roundout the presentation. Key words. LeonhardEuler, sketch of Euler’s life, works, andpersonality AMS subject classification. 01A50 DOI. 10.1137/070702710 Seh ich die Werke der Meister an, So sehe ich, was sie getan; Betracht ich meine Siebensachen, Seh ich, was ich h¨att sollen machen. –Goethe, Weimar 1814/1815 1. Introduction. It is a virtually impossible task to do justice, in a short span of time and space, to the great genius of Leonhard Euler. All we can do, in this lecture, is to bring across some glimpses of Euler’s incredibly voluminous and diverse work, which today fills 74 massive volumes of the Opera omnia (with two more to come). Nine additional volumes of correspondence are planned and have already appeared in part, and about seven volumes of notebooks and diaries still await editing! We begin in section 2 with a brief outline of Euler’s life, going through the three stations of his life: Basel, St.
    [Show full text]
  • Upwind Summation by Parts Finite Difference Methods for Large Scale
    Upwind summation by parts finite difference methods for large scale elastic wave simulations in 3D complex geometries ? Kenneth Durua,∗, Frederick Funga, Christopher Williamsa aMathematical Sciences Institute, Australian National University, Australia. Abstract High-order accurate summation-by-parts (SBP) finite difference (FD) methods constitute efficient numerical methods for simulating large-scale hyperbolic wave propagation problems. Traditional SBP FD operators that approximate first-order spatial derivatives with central-difference stencils often have spurious unresolved numerical wave-modes in their computed solutions. Recently derived high order accurate upwind SBP operators based non-central (upwind) FD stencils have the potential to suppress these poisonous spurious wave-modes on marginally resolved computational grids. In this paper, we demonstrate that not all high order upwind SBP FD operators are applicable. Numerical dispersion relation analysis shows that odd-order upwind SBP FD operators also support spurious unresolved high-frequencies on marginally resolved meshes. Meanwhile, even-order upwind SBP FD operators (of order 2; 4; 6) do not support spurious unresolved high frequency wave modes and also have better numerical dispersion properties. For all the upwind SBP FD operators we discretise the three space dimensional (3D) elastic wave equation on boundary-conforming curvilinear meshes. Using the energy method we prove that the semi-discrete ap- proximation is stable and energy-conserving. We derive a priori error estimate and prove the convergence of the numerical error. Numerical experiments for the 3D elastic wave equation in complex geometries corrobo- rate the theoretical analysis. Numerical simulations of the 3D elastic wave equation in heterogeneous media with complex non-planar free surface topography are given, including numerical simulations of community developed seismological benchmark problems.
    [Show full text]
  • High Order Gradient, Curl and Divergence Conforming Spaces, with an Application to NURBS-Based Isogeometric Analysis
    High order gradient, curl and divergence conforming spaces, with an application to compatible NURBS-based IsoGeometric Analysis R.R. Hiemstraa, R.H.M. Huijsmansa, M.I.Gerritsmab aDepartment of Marine Technology, Mekelweg 2, 2628CD Delft bDepartment of Aerospace Technology, Kluyverweg 2, 2629HT Delft Abstract Conservation laws, in for example, electromagnetism, solid and fluid mechanics, allow an exact discrete representation in terms of line, surface and volume integrals. We develop high order interpolants, from any basis that is a partition of unity, that satisfy these integral relations exactly, at cell level. The resulting gradient, curl and divergence conforming spaces have the propertythat the conservationlaws become completely independent of the basis functions. This means that the conservation laws are exactly satisfied even on curved meshes. As an example, we develop high ordergradient, curl and divergence conforming spaces from NURBS - non uniform rational B-splines - and thereby generalize the compatible spaces of B-splines developed in [1]. We give several examples of 2D Stokes flow calculations which result, amongst others, in a point wise divergence free velocity field. Keywords: Compatible numerical methods, Mixed methods, NURBS, IsoGeometric Analyis Be careful of the naive view that a physical law is a mathematical relation between previously defined quantities. The situation is, rather, that a certain mathematical structure represents a given physical structure. Burke [2] 1. Introduction In deriving mathematical models for physical theories, we frequently start with analysis on finite dimensional geometric objects, like a control volume and its bounding surfaces. We assign global, ’measurable’, quantities to these different geometric objects and set up balance statements.
    [Show full text]
  • A Brief Introduction to Numerical Methods for Differential Equations
    A Brief Introduction to Numerical Methods for Differential Equations January 10, 2011 This tutorial introduces some basic numerical computation techniques that are useful for the simulation and analysis of complex systems modelled by differential equations. Such differential models, especially those partial differential ones, have been extensively used in various areas from astronomy to biology, from meteorology to finance. However, if we ignore the differences caused by applications and focus on the mathematical equations only, a fundamental question will arise: Can we predict the future state of a system from a known initial state and the rules describing how it changes? If we can, how to make the prediction? This problem, known as Initial Value Problem(IVP), is one of those problems that we are most concerned about in numerical analysis for differential equations. In this tutorial, Euler method is used to solve this problem and a concrete example of differential equations, the heat diffusion equation, is given to demonstrate the techniques talked about. But before introducing Euler method, numerical differentiation is discussed as a prelude to make you more comfortable with numerical methods. 1 Numerical Differentiation 1.1 Basic: Forward Difference Derivatives of some simple functions can be easily computed. However, if the function is too compli- cated, or we only know the values of the function at several discrete points, numerical differentiation is a tool we can rely on. Numerical differentiation follows an intuitive procedure. Recall what we know about the defini- tion of differentiation: df f(x + h) − f(x) = f 0(x) = lim dx h!0 h which means that the derivative of function f(x) at point x is the difference between f(x + h) and f(x) divided by an infinitesimal h.
    [Show full text]
  • The Pascal Matrix Function and Its Applications to Bernoulli Numbers and Bernoulli Polynomials and Euler Numbers and Euler Polynomials
    The Pascal Matrix Function and Its Applications to Bernoulli Numbers and Bernoulli Polynomials and Euler Numbers and Euler Polynomials Tian-Xiao He ∗ Jeff H.-C. Liao y and Peter J.-S. Shiue z Dedicated to Professor L. C. Hsu on the occasion of his 95th birthday Abstract A Pascal matrix function is introduced by Call and Velleman in [3]. In this paper, we will use the function to give a unified approach in the study of Bernoulli numbers and Bernoulli poly- nomials. Many well-known and new properties of the Bernoulli numbers and polynomials can be established by using the Pascal matrix function. The approach is also applied to the study of Euler numbers and Euler polynomials. AMS Subject Classification: 05A15, 65B10, 33C45, 39A70, 41A80. Key Words and Phrases: Pascal matrix, Pascal matrix func- tion, Bernoulli number, Bernoulli polynomial, Euler number, Euler polynomial. ∗Department of Mathematics, Illinois Wesleyan University, Bloomington, Illinois 61702 yInstitute of Mathematics, Academia Sinica, Taipei, Taiwan zDepartment of Mathematical Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, 89154-4020. This work is partially supported by the Tzu (?) Tze foundation, Taipei, Taiwan, and the Institute of Mathematics, Academia Sinica, Taipei, Taiwan. The author would also thank to the Institute of Mathematics, Academia Sinica for the hospitality. 1 2 T. X. He, J. H.-C. Liao, and P. J.-S. Shiue 1 Introduction A large literature scatters widely in books and journals on Bernoulli numbers Bn, and Bernoulli polynomials Bn(x). They can be studied by means of the binomial expression connecting them, n X n B (x) = B xn−k; n ≥ 0: (1) n k k k=0 The study brings consistent attention of researchers working in combi- natorics, number theory, etc.
    [Show full text]
  • Numerical Stability & Numerical Smoothness of Ordinary Differential
    NUMERICAL STABILITY & NUMERICAL SMOOTHNESS OF ORDINARY DIFFERENTIAL EQUATIONS Kaitlin Reddinger A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF ARTS August 2015 Committee: Tong Sun, Advisor So-Hsiang Chou Kimberly Rogers ii ABSTRACT Tong Sun, Advisor Although numerically stable algorithms can be traced back to the Babylonian period, it is be- lieved that the study of numerical methods for ordinary differential equations was not rigorously developed until the 1700s. Since then the field has expanded - first with Leonhard Euler’s method and then with the works of Augustin Cauchy, Carl Runge and Germund Dahlquist. Now applica- tions involving numerical methods can be found in a myriad of subjects. With several centuries worth of diligent study devoted to the crafting of well-conditioned problems, it is surprising that one issue in particular - numerical stability - continues to cloud the analysis and implementation of numerical approximation. According to professor Paul Glendinning from the University of Cambridge, “The stability of solutions of differential equations can be a very difficult property to pin down. Rigorous mathemat- ical definitions are often too prescriptive and it is not always clear which properties of solutions or equations are most important in the context of any particular problem. In practice, different definitions are used (or defined) according to the problem being considered. The effect of this confusion is that there are more than 57 varieties of stability to choose from” [10]. Although this quote is primarily in reference to nonlinear problems, it can most certainly be applied to the topic of numerical stability in general.
    [Show full text]