Syllabus and homework problems for Math 423

Text Book:  Partial Differential Equations: An Introduction, 3rd Edition, Walter A. Strauss, John Wiley & Sons

Date Topics covered Section Homework problems
1/20 What is a Partial Differential Equation? 1.1 10, 12
1/24 First-order Linear Equations (Solution in the constant-coefficient case; the variable-coefficient case and characteristic curves. 1.2 3, 6, 7, 9
1/27 Flows, Vibrations and Diffusions (Derivations of PDEs in various physical situations; e.g., the vibrating string, the vibrating drumhead, diffusion, heat flow, hydrogen atom). 1.3 2, 4, 9
1/31 Initial and boundary conditions (the Dirichlet, Neumann and Robin conditions and their significance for the vibrating string and diffusion equations.  Conditions at infinity.) 1.4
2/3 Well- (and ill-)Posed Problems. 1.5 1, 2
2/7 Types of second-order equations. 1.6 2, 4
2/10 The Wave Equation (D'Alembert's solution on the line; the plucked string). 2.1 2, 4
2/14 Causality and Energy. 2.2
2/17 The Diffusion (or Heat) Equation (the maximum principle; uniqueness for the Dirichlet problem). 2.3 1, 4, 5
2/21 Diffusion on the whole real line (the Gaussian or fundamental solution). 2.4 1, 3, 6, 9
2/24 First Midterm (regular class hour and location; covers 1.1 through 2.3)
2/28 Comparison of waves and diffusion. 2.5
3/3 Separation of Variables, the Dirichlet Condition (both for the wave and the diffusion equations). 4.1 1, 2, 3, 6
3/7 The Neumann Condition. 4.2 1, 2, 3
3/10 Robin's Conditions (cases in which zero is an eigenvalue and cases in which one eigenvalue is negative). 4.3 1, 2, 7, 9, 17
3/21 The Coefficients (or discrete Fourier transform): formulas for the coefficients, applications to the wave and the diffusion equations. 5.1 1, 2, 4, 8
3/24  Even, Odd, Periodic and Complex-valued functions. 5.2 1, 4, 11, 15
3/28 Orthogonality and "General Fourier Series" (orthogonal systems from symmetric boundary conditions; complex eigenvalues) 5.3 1, 2, 6, 12, 13
3/31 Completeness (three notions of convergence: pointwise, uniform and mean-square: convergence results for Fourier series and their generalizations). 5.4 1, 3, 11, 16
4/4 Completeness and the Gibbs phenomenon. 5.5 1, 2, 11, 13
4/7 Second Midterm (regular class hour and location; covers 2.4 through 5.4)
4/11 Inhomogeneous Boundary Conditions. 5.6 1, 5, 6, 13
4/14 The Laplace Equation (its physical significance, maximum principle, uniqueness of solutions of the Dirichlet Problem, invariance of the Laplace operator under rigid motions). 6.1 1, 2, 4, 10
4/18 Rectangles and Cubes. 6.2 2, 4, 7
4/21 Green's First Identity (and some consequences). 7.1 1, 4, 6
4/25 Green's Second Identity (and some consequences). 7.2 1, 2
4/28 Green's Functions and the Dirichlet Problem. 7.3 1, 2
5/2 Half-Spaces and Spheres. 7.4 1, 7, 8, 13
5/5 Final exam, 8:00 to 11:00 am (location to be announced)