A Brief Tour of Vector Calculus

Total Page:16

File Type:pdf, Size:1020Kb

A Brief Tour of Vector Calculus A BRIEF TOUR OF VECTOR CALCULUS A. HAVENS Contents 0 Prelude ii 1 Directional Derivatives, the Gradient and the Del Operator 1 1.1 Conceptual Review: Directional Derivatives and the Gradient........... 1 1.2 The Gradient as a Vector Field............................ 5 1.3 The Gradient Flow and Critical Points ....................... 10 1.4 The Del Operator and the Gradient in Other Coordinates*............ 17 1.5 Problems........................................ 21 2 Vector Fields in Low Dimensions 26 2 3 2.1 General Vector Fields in Domains of R and R . 26 2.2 Flows and Integral Curves .............................. 31 2.3 Conservative Vector Fields and Potentials...................... 32 2.4 Vector Fields from Frames*.............................. 37 2.5 Divergence, Curl, Jacobians, and the Laplacian................... 41 2.6 Parametrized Surfaces and Coordinate Vector Fields*............... 48 2.7 Tangent Vectors, Normal Vectors, and Orientations*................ 52 2.8 Problems........................................ 58 3 Line Integrals 66 3.1 Defining Scalar Line Integrals............................. 66 3.2 Line Integrals in Vector Fields ............................ 75 3.3 Work in a Force Field................................. 78 3.4 The Fundamental Theorem of Line Integrals .................... 79 3.5 Motion in Conservative Force Fields Conserves Energy .............. 81 3.6 Path Independence and Corollaries of the Fundamental Theorem......... 82 3.7 Green's Theorem.................................... 84 3.8 Problems........................................ 89 4 Surface Integrals, Flux, and Fundamental Theorems 93 4.1 Surface Integrals of Scalar Fields........................... 93 4.2 Flux........................................... 96 4.3 The Gradient, Divergence, and Curl Operators Via Limits* . 103 4.4 The Stokes-Kelvin Theorem..............................108 4.5 The Divergence Theorem ...............................112 4.6 Problems........................................114 List of Figures 117 i 11/14/19 Multivariate Calculus: Vector Calculus Havens 0. Prelude This is an ongoing notes project to capture the essence of the subject of vector calculus by providing a variety of examples and visualizations, but also to present the main ideas of vector calculus in conceptual a framework that is adequate for the needs of mathematics, physics, and engineering majors. The essential prerequisites are • comfort with college level algebra, analytic geometry and trigonometry, • calculus knowledge including exposure to multivariable functions, partial derivatives and multiple integrals, • the material of my notes on Vector Algebra, and the Equations of Lines and Planes in 3-Space or equivalent, and • the material related to polar, cylindrical and spherical frames in my notes on Curvature, Natural Frames, and Acceleration for Plane and Space Curves, particularly for the optional sections. Definitions and results are sometimes stated in terms of functions of n variables for an arbitrary number n ≥ 2, but examples focus on n = 2 and n = 3. Since it is hard to really see what is happening for n ≥ 4, pictures often show up for examples using n = 2 or 3, and the hope is that you internalize some intuition from these pictures and examples. If you have trouble understanding a statement that uses arbitrary n, just read it with n = 2 or n = 3 and try to understand the underlying geometry in these cases. A warning: my notational conventions sometimes differ from other common sources, so use cau- tion when comparing to other resources on vector calculus. In particular, my spherical coordinate system is not the one in most common use, but is an intuitive convention nonetheless, as explained in Curvature, Natural Frames, and Acceleration for Plane and Space Curves, where they are con- structed so as to adapt geographers' conventions for latitude and longitude. These notes exist primarily to prop up the problems; the exposition and ideas herein are foremost to introduce enough language for the reader to then approach and tackle the various problems provided. Some of the problems are quite standard and are meant to drive home a particular concept, while others encourage you to fill in details omitted in examples, and a few problems are meant to give a flavor of a more advanced but mathematical subject, such as the study of differential equations, or topology. There's also a handful of computational problems meant to satisfy those who merely enjoy the meditative art of symbol pushing, but the bulk of the questions ought to provoke some serious thought about how the objects of vector calculus interact with each other and with mathematical models of the real world. In addition to clarifying notations and terminology, footnotes are often used to exposit on more advanced directions, and hint at how the subject matter broadens and connects to contemporary mathematical thinking and research. Finally, please forgive any typos and the clunkiness of formatting; these and the compan- ion/prerequisite notes are work in progress that were primarily hastily assembled in the midst of my terminal years teaching at University of Massachusetts Amherst as a PhD student. I welcome suggestions as I work to improve these. ii 11/14/19 Multivariate Calculus: Vector Calculus Havens 1. Directional Derivatives, the Gradient and the Del Operator § 1.1. Conceptual Review: Directional Derivatives and the Gradient Recall that partial derivatives are defined by computing a difference quotient in which only one variable is perturbed. This has a geometric interpretation as slicing the graph of the function along a plane parallel to the directions of the coordinate of concern xi and the coordinate of the dependent variable whose value is f(x1; : : : ; xi; : : : ; xn) (so this plane is thus normal to the coordinate directions of the variables held constant), and then measuring the rate of change of the function along the curve of intersection, as a function of the variable xi. In two variables, the slicing for the two partial derivatives corresponds to a picture like that of figure1. Figure 1. Curves C1 and C2 on the graph of a function along planes of constant y and x respectively. This geometric picture suggests that we need not be confined to only know the rate of change of the function along coordinate directions, for we could slice the graph along any plane containing the direction of the dependent variable. This gives rise to the notion of a directional derivative, defined so as to allow us to measure the rate of change of a function f in any of the possible directions we might choose as we leave a point of the function's domain. n Fix a connected domain D ⊂ R , and let f : D! R be a multivariate function of n variables, and r = hx1; : : : xni an arbitrary position vector for a point P of D. We'll often conflate the idea of D as a set of points with the conception of it as a set of positions, and thus will unapologetically write things such as r 2 D to mean that the point (x1; : : : ; xn) with position r is an element of D. Definitions will often be stated in the general context of arbitrary n, but examples and pictures will be specialized to low dimensions. Observe that a \direction" at a point r 2 D may be specified by giving a unit vector, i.e. a vector u^ of length 1. In two dimensions, the set of unit vectors, and thus, of directions, is a circle, while in 1 11/14/19 Multivariate Calculus: Vector Calculus Havens n three dimensions it is the surface of a sphere. The set of unit vectors in R geometrically describes n the origin centered (n − 1)-dimensional sphere in R : n−1 n S = fr 2 R : krk = 1g : n−1 Definition. Given a unit vector u^ 2 S and a function f : D! R of n variables, the directional derivative of f in the direction of u^ at a point r0 2 D is f(r0 + hu^) − f(r0) Du^ f(r0) = lim : h!0 h Again, in two dimensions we can actually see and interpret this limit in terms of the familiar notion of a slope of a tangent line. This, together with our discussion of the gradient in two dimensions, will set the stage for understanding tangent space objects later. Figure 2. The directional derivative computes a slope to a curve of intersection of a vertical plane slicing the graph surface in the direction specified by a unit vector. 3 Recall that the graph Gf of a two-variable function f(x; y) is the locus of points (x; y; z) 2 R satisfying z = f(x; y). For f continuously differentiable, this is a smooth1 surface over D. Fix a point 1 r0 2 D at which we are interested in the directional derivative in the direction of a given u^ 2 S . ^ ^ Note that u^ and k determine a plane Πu^;r0 containing the point r0 + f(r0)k = hx0; y0; f(x0; y0)i, and this plane slices the surface Gf along some curve. In the plane Πu^;r0 , the variation of the curve as one displaces from r0 in the direction of ±u^ is purely in the z direction, and so it is natural to try to study the rate of change of z as one moves along the u^ direction by a small displacement hu^. One sees easily that the directional derivative formula above is precisely the appropriate limit of a difference quotient to capture this rate of change. Observe also that the usual partial derivatives are 3 just directional derivatives along the coordinate directions, e.g. for R with standard rectangular 2 11/14/19 Multivariate Calculus: Vector Calculus Havens coordinates (x; y; z), one has: @ @ @ D = ;D = ;D = : ^ı @x ^ @y k^ @z Proposition 1.1. The directional derivative of f in the direction of u^ at a point r0 2 D may be calculated as n @f D f(r ) = X u (r ) ; u^ 0 i @x 0 i=1 i n where ui are the components of u^ in rectangular coordinates on R and xi are the n variables of f giving the rectangular coordinates of a general vector argument r.
Recommended publications
  • Lecture 11 Line Integrals of Vector-Valued Functions (Cont'd)
    Lecture 11 Line integrals of vector-valued functions (cont’d) In the previous lecture, we considered the following physical situation: A force, F(x), which is not necessarily constant in space, is acting on a mass m, as the mass moves along a curve C from point P to point Q as shown in the diagram below. z Q P m F(x(t)) x(t) C y x The goal is to compute the total amount of work W done by the force. Clearly the constant force/straight line displacement formula, W = F · d , (1) where F is force and d is the displacement vector, does not apply here. But the fundamental idea, in the “Spirit of Calculus,” is to break up the motion into tiny pieces over which we can use Eq. (1 as an approximation over small pieces of the curve. We then “sum up,” i.e., integrate, over all contributions to obtain W . The total work is the line integral of the vector field F over the curve C: W = F · dx . (2) ZC Here, we summarize the main steps involved in the computation of this line integral: 1. Step 1: Parametrize the curve C We assume that the curve C can be parametrized, i.e., x(t)= g(t) = (x(t),y(t), z(t)), t ∈ [a, b], (3) so that g(a) is point P and g(b) is point Q. From this parametrization we can compute the velocity vector, ′ ′ ′ ′ v(t)= g (t) = (x (t),y (t), z (t)) . (4) 1 2. Step 2: Compute field vector F(g(t)) over curve C F(g(t)) = F(x(t),y(t), z(t)) (5) = (F1(x(t),y(t), z(t), F2(x(t),y(t), z(t), F3(x(t),y(t), z(t))) , t ∈ [a, b] .
    [Show full text]
  • Chapter 11. Three Dimensional Analytic Geometry and Vectors
    Chapter 11. Three dimensional analytic geometry and vectors. Section 11.5 Quadric surfaces. Curves in R2 : x2 y2 ellipse + =1 a2 b2 x2 y2 hyperbola − =1 a2 b2 parabola y = ax2 or x = by2 A quadric surface is the graph of a second degree equation in three variables. The most general such equation is Ax2 + By2 + Cz2 + Dxy + Exz + F yz + Gx + Hy + Iz + J =0, where A, B, C, ..., J are constants. By translation and rotation the equation can be brought into one of two standard forms Ax2 + By2 + Cz2 + J =0 or Ax2 + By2 + Iz =0 In order to sketch the graph of a quadric surface, it is useful to determine the curves of intersection of the surface with planes parallel to the coordinate planes. These curves are called traces of the surface. Ellipsoids The quadric surface with equation x2 y2 z2 + + =1 a2 b2 c2 is called an ellipsoid because all of its traces are ellipses. 2 1 x y 3 2 1 z ±1 ±2 ±3 ±1 ±2 The six intercepts of the ellipsoid are (±a, 0, 0), (0, ±b, 0), and (0, 0, ±c) and the ellipsoid lies in the box |x| ≤ a, |y| ≤ b, |z| ≤ c Since the ellipsoid involves only even powers of x, y, and z, the ellipsoid is symmetric with respect to each coordinate plane. Example 1. Find the traces of the surface 4x2 +9y2 + 36z2 = 36 1 in the planes x = k, y = k, and z = k. Identify the surface and sketch it. Hyperboloids Hyperboloid of one sheet. The quadric surface with equations x2 y2 z2 1.
    [Show full text]
  • Pure Torsion Problem in Tensor Notation [3] Sual I
    56 Budownictwo i Architektura 18(1) (2019) 57-6961-73 DOI: 10.24358/Bud-Arch_19_181_06 7. References: [1] EN 206-1:2013, Concrete – Part 1: Specification, performance, production and conformity. [2] Holicky, M., Vorlicek. M., Fractile estimation and sampling inspection in building, Acta Polytechnica, CVUT Praha, 1992.Vol. 32. Issue 1, 87-96. Pure torsion problem in tensor notation [3] Sual I. Gass, and Arjang A. Assad, An annotated timeline of operation research. An informal history. Springer Science and Business Media, 2005. Sławomir Karaś [4] Harrison. T.A., Crompton, S., Eastwood. C., Richardson. G., Sym, R., Guidance on the application of the EN 206-1 conformity rules, Quarry Products Association, 2001. Department of Roads and Bridges, Faculty of Civil Engineering and Architecture, Lublin University of Technology, e–mail: [email protected] [5] Czarnecki, L. et al., Concrete according to PN EN 206-1- The comment - Collective work, Polish ORCID: 0000-0002-0626-5582 Cement and PKN, Cracow, Poland, 2004. [6] Lynch, B., Kelly, J., McGrath, M., Murphy, B., Newell, J., The new Concrete Standards, An Abstract: The paper examines the application of the tensor calculus to the classic Introduction to EN 206-1, The Irish Concrete Society, 2004. problem of the pure torsion of prismatic rods. The introduction contains a short description [7] Montgomery, D.C., Introduction to Statistical Quality Control, 5th Ed., Wiley, 2005. of the reference frames, base vectors, contravariant and covariant vector coordinates when [8] Taerwe, L., Evaluation of compound compliance criteria for concrete strength, Materials and applying the Einstein summation convention. Torsion formulas were derived according to Structures, 1998, 21, pp.
    [Show full text]
  • Pencils of Quadrics
    Europ. J. Combinatorics (1988) 9, 255-270 Intersections in Projective Space II: Pencils of Quadrics A. A. BRUEN AND J. w. P. HIRSCHFELD A complete classification is given of pencils of quadrics in projective space of three dimensions over a finite field, where each pencil contains at least one non-singular quadric and where the base curve is not absolutely irreducible. This leads to interesting configurations in the space such as partitions by elliptic quadrics and by lines. 1. INTRODUCTION A pencil of quadrics in PG(3, q) is non-singular if it contains at least one non-singular quadric. The base of a pencil is a quartic curve and is reducible if over some extension of GF(q) it splits into more than one component: four lines, two lines and a conic, two conics, or a line and a twisted cubic. In order to contain no points or to contain some line over GF(q), the base is necessarily reducible. In the main part of this paper a classification is given of non-singular pencils ofquadrics in L = PG(3, q) with a reducible base. This leads to geometrically interesting configur­ ations obtained from elliptic and hyperbolic quadrics, such as spreads and partitions of L. The remaining part of the paper deals with the case when the base is not reducible and is therefore a rational or elliptic quartic. The number of points in the elliptic case is then governed by the Hasse formula. However, we are able to derive an interesting combi­ natorial relationship, valid also in higher dimensions, between the number of points in the base curve and the number in the base curve of a dual pencil.
    [Show full text]
  • MULTIVARIABLE CALCULUS (MATH 212 ) COMMON TOPIC LIST (Approved by the Occidental College Math Department on August 28, 2009)
    MULTIVARIABLE CALCULUS (MATH 212 ) COMMON TOPIC LIST (Approved by the Occidental College Math Department on August 28, 2009) Required Topics • Multivariable functions • 3-D space o Distance o Equations of Spheres o Graphing Planes Spheres Miscellaneous function graphs Sections and level curves (contour diagrams) Level surfaces • Planes o Equations of planes, in different forms o Equation of plane from three points o Linear approximation and tangent planes • Partial Derivatives o Compute using the definition of partial derivative o Compute using differentiation rules o Interpret o Approximate, given contour diagram, table of values, or sketch of sections o Signs from real-world description o Compute a gradient vector • Vectors o Arithmetic on vectors, pictorially and by components o Dot product compute using components v v v v v ⋅ w = v w cosθ v v v v u ⋅ v = 0⇔ u ⊥ v (for nonzero vectors) o Cross product Direction and length compute using components and determinant • Directional derivatives o estimate from contour diagram o compute using the lim definition t→0 v v o v compute using fu = ∇f ⋅ u ( u a unit vector) • Gradient v o v geometry (3 facts, and understand how they follow from fu = ∇f ⋅ u ) Gradient points in direction of fastest increase Length of gradient is the directional derivative in that direction Gradient is perpendicular to level set o given contour diagram, draw a gradient vector • Chain rules • Higher-order partials o compute o mixed partials are equal (under certain conditions) • Optimization o Locate and
    [Show full text]
  • Notes on Calculus II Integral Calculus Miguel A. Lerma
    Notes on Calculus II Integral Calculus Miguel A. Lerma November 22, 2002 Contents Introduction 5 Chapter 1. Integrals 6 1.1. Areas and Distances. The Definite Integral 6 1.2. The Evaluation Theorem 11 1.3. The Fundamental Theorem of Calculus 14 1.4. The Substitution Rule 16 1.5. Integration by Parts 21 1.6. Trigonometric Integrals and Trigonometric Substitutions 26 1.7. Partial Fractions 32 1.8. Integration using Tables and CAS 39 1.9. Numerical Integration 41 1.10. Improper Integrals 46 Chapter 2. Applications of Integration 50 2.1. More about Areas 50 2.2. Volumes 52 2.3. Arc Length, Parametric Curves 57 2.4. Average Value of a Function (Mean Value Theorem) 61 2.5. Applications to Physics and Engineering 63 2.6. Probability 69 Chapter 3. Differential Equations 74 3.1. Differential Equations and Separable Equations 74 3.2. Directional Fields and Euler’s Method 78 3.3. Exponential Growth and Decay 80 Chapter 4. Infinite Sequences and Series 83 4.1. Sequences 83 4.2. Series 88 4.3. The Integral and Comparison Tests 92 4.4. Other Convergence Tests 96 4.5. Power Series 98 4.6. Representation of Functions as Power Series 100 4.7. Taylor and MacLaurin Series 103 3 CONTENTS 4 4.8. Applications of Taylor Polynomials 109 Appendix A. Hyperbolic Functions 113 A.1. Hyperbolic Functions 113 Appendix B. Various Formulas 118 B.1. Summation Formulas 118 Appendix C. Table of Integrals 119 Introduction These notes are intended to be a summary of the main ideas in course MATH 214-2: Integral Calculus.
    [Show full text]
  • The Matrix Calculus You Need for Deep Learning
    The Matrix Calculus You Need For Deep Learning Terence Parr and Jeremy Howard July 3, 2018 (We teach in University of San Francisco's MS in Data Science program and have other nefarious projects underway. You might know Terence as the creator of the ANTLR parser generator. For more material, see Jeremy's fast.ai courses and University of San Francisco's Data Institute in- person version of the deep learning course.) HTML version (The PDF and HTML were generated from markup using bookish) Abstract This paper is an attempt to explain all the matrix calculus you need in order to understand the training of deep neural networks. We assume no math knowledge beyond what you learned in calculus 1, and provide links to help you refresh the necessary math where needed. Note that you do not need to understand this material before you start learning to train and use deep learning in practice; rather, this material is for those who are already familiar with the basics of neural networks, and wish to deepen their understanding of the underlying math. Don't worry if you get stuck at some point along the way|just go back and reread the previous section, and try writing down and working through some examples. And if you're still stuck, we're happy to answer your questions in the Theory category at forums.fast.ai. Note: There is a reference section at the end of the paper summarizing all the key matrix calculus rules and terminology discussed here. arXiv:1802.01528v3 [cs.LG] 2 Jul 2018 1 Contents 1 Introduction 3 2 Review: Scalar derivative rules4 3 Introduction to vector calculus and partial derivatives5 4 Matrix calculus 6 4.1 Generalization of the Jacobian .
    [Show full text]
  • Vector Calculus and Multiple Integrals Rob Fender, HT 2018
    Vector Calculus and Multiple Integrals Rob Fender, HT 2018 COURSE SYNOPSIS, RECOMMENDED BOOKS Course syllabus (on which exams are based): Double integrals and their evaluation by repeated integration in Cartesian, plane polar and other specified coordinate systems. Jacobians. Line, surface and volume integrals, evaluation by change of variables (Cartesian, plane polar, spherical polar coordinates and cylindrical coordinates only unless the transformation to be used is specified). Integrals around closed curves and exact differentials. Scalar and vector fields. The operations of grad, div and curl and understanding and use of identities involving these. The statements of the theorems of Gauss and Stokes with simple applications. Conservative fields. Recommended Books: Mathematical Methods for Physics and Engineering (Riley, Hobson and Bence) This book is lazily referred to as “Riley” throughout these notes (sorry, Drs H and B) You will all have this book, and it covers all of the maths of this course. However it is rather terse at times and you will benefit from looking at one or both of these: Introduction to Electrodynamics (Griffiths) You will buy this next year if you haven’t already, and the chapter on vector calculus is very clear Div grad curl and all that (Schey) A nice discussion of the subject, although topics are ordered differently to most courses NB: the latest version of this book uses the opposite convention to polar coordinates to this course (and indeed most of physics), but older versions can often be found in libraries 1 Week One A review of vectors, rotation of coordinate systems, vector vs scalar fields, integrals in more than one variable, first steps in vector differentiation, the Frenet-Serret coordinate system Lecture 1 Vectors A vector has direction and magnitude and is written in these notes in bold e.g.
    [Show full text]
  • Symmetry and Tensors Rotations and Tensors
    Symmetry and tensors Rotations and tensors A rotation of a 3-vector is accomplished by an orthogonal transformation. Represented as a matrix, A, we replace each vector, v, by a rotated vector, v0, given by multiplying by A, 0 v = Av In index notation, 0 X vm = Amnvn n Since a rotation must preserve lengths of vectors, we require 02 X 0 0 X 2 v = vmvm = vmvm = v m m Therefore, X X 0 0 vmvm = vmvm m m ! ! X X X = Amnvn Amkvk m n k ! X X = AmnAmk vnvk k;n m Since xn is arbitrary, this is true if and only if X AmnAmk = δnk m t which we can rewrite using the transpose, Amn = Anm, as X t AnmAmk = δnk m In matrix notation, this is t A A = I where I is the identity matrix. This is equivalent to At = A−1. Multi-index objects such as matrices, Mmn, or the Levi-Civita tensor, "ijk, have definite transformation properties under rotations. We call an object a (rotational) tensor if each index transforms in the same way as a vector. An object with no indices, that is, a function, does not transform at all and is called a scalar. 0 A matrix Mmn is a (second rank) tensor if and only if, when we rotate vectors v to v , its new components are given by 0 X Mmn = AmjAnkMjk jk This is what we expect if we imagine Mmn to be built out of vectors as Mmn = umvn, for example. In the same way, we see that the Levi-Civita tensor transforms as 0 X "ijk = AilAjmAkn"lmn lmn 1 Recall that "ijk, because it is totally antisymmetric, is completely determined by only one of its components, say, "123.
    [Show full text]
  • Differentiation Rules (Differential Calculus)
    Differentiation Rules (Differential Calculus) 1. Notation The derivative of a function f with respect to one independent variable (usually x or t) is a function that will be denoted by D f . Note that f (x) and (D f )(x) are the values of these functions at x. 2. Alternate Notations for (D f )(x) d d f (x) d f 0 (1) For functions f in one variable, x, alternate notations are: Dx f (x), dx f (x), dx , dx (x), f (x), f (x). The “(x)” part might be dropped although technically this changes the meaning: f is the name of a function, dy 0 whereas f (x) is the value of it at x. If y = f (x), then Dxy, dx , y , etc. can be used. If the variable t represents time then Dt f can be written f˙. The differential, “d f ”, and the change in f ,“D f ”, are related to the derivative but have special meanings and are never used to indicate ordinary differentiation. dy 0 Historical note: Newton used y,˙ while Leibniz used dx . About a century later Lagrange introduced y and Arbogast introduced the operator notation D. 3. Domains The domain of D f is always a subset of the domain of f . The conventional domain of f , if f (x) is given by an algebraic expression, is all values of x for which the expression is defined and results in a real number. If f has the conventional domain, then D f usually, but not always, has conventional domain. Exceptions are noted below.
    [Show full text]
  • Appendix a Short Course in Taylor Series
    Appendix A Short Course in Taylor Series The Taylor series is mainly used for approximating functions when one can identify a small parameter. Expansion techniques are useful for many applications in physics, sometimes in unexpected ways. A.1 Taylor Series Expansions and Approximations In mathematics, the Taylor series is a representation of a function as an infinite sum of terms calculated from the values of its derivatives at a single point. It is named after the English mathematician Brook Taylor. If the series is centered at zero, the series is also called a Maclaurin series, named after the Scottish mathematician Colin Maclaurin. It is common practice to use a finite number of terms of the series to approximate a function. The Taylor series may be regarded as the limit of the Taylor polynomials. A.2 Definition A Taylor series is a series expansion of a function about a point. A one-dimensional Taylor series is an expansion of a real function f(x) about a point x ¼ a is given by; f 00ðÞa f 3ðÞa fxðÞ¼faðÞþf 0ðÞa ðÞþx À a ðÞx À a 2 þ ðÞx À a 3 þÁÁÁ 2! 3! f ðÞn ðÞa þ ðÞx À a n þÁÁÁ ðA:1Þ n! © Springer International Publishing Switzerland 2016 415 B. Zohuri, Directed Energy Weapons, DOI 10.1007/978-3-319-31289-7 416 Appendix A: Short Course in Taylor Series If a ¼ 0, the expansion is known as a Maclaurin Series. Equation A.1 can be written in the more compact sigma notation as follows: X1 f ðÞn ðÞa ðÞx À a n ðA:2Þ n! n¼0 where n ! is mathematical notation for factorial n and f(n)(a) denotes the n th derivation of function f evaluated at the point a.
    [Show full text]
  • Multivariable and Vector Calculus
    Multivariable and Vector Calculus Lecture Notes for MATH 0200 (Spring 2015) Frederick Tsz-Ho Fong Department of Mathematics Brown University Contents 1 Three-Dimensional Space ....................................5 1.1 Rectangular Coordinates in R3 5 1.2 Dot Product7 1.3 Cross Product9 1.4 Lines and Planes 11 1.5 Parametric Curves 13 2 Partial Differentiations ....................................... 19 2.1 Functions of Several Variables 19 2.2 Partial Derivatives 22 2.3 Chain Rule 26 2.4 Directional Derivatives 30 2.5 Tangent Planes 34 2.6 Local Extrema 36 2.7 Lagrange’s Multiplier 41 2.8 Optimizations 46 3 Multiple Integrations ........................................ 49 3.1 Double Integrals in Rectangular Coordinates 49 3.2 Fubini’s Theorem for General Regions 53 3.3 Double Integrals in Polar Coordinates 57 3.4 Triple Integrals in Rectangular Coordinates 62 3.5 Triple Integrals in Cylindrical Coordinates 67 3.6 Triple Integrals in Spherical Coordinates 70 4 Vector Calculus ............................................ 75 4.1 Vector Fields on R2 and R3 75 4.2 Line Integrals of Vector Fields 83 4.3 Conservative Vector Fields 88 4.4 Green’s Theorem 98 4.5 Parametric Surfaces 105 4.6 Stokes’ Theorem 120 4.7 Divergence Theorem 127 5 Topics in Physics and Engineering .......................... 133 5.1 Coulomb’s Law 133 5.2 Introduction to Maxwell’s Equations 137 5.3 Heat Diffusion 141 5.4 Dirac Delta Functions 144 1 — Three-Dimensional Space 1.1 Rectangular Coordinates in R3 Throughout the course, we will use an ordered triple (x, y, z) to represent a point in the three dimensional space.
    [Show full text]