Math 322 Applied Mathematical Analysis II, FALL 2019

Basic Partial differential Equations (PDEs) and solution techniques, Fourier series and integrals, special functions

homework

Hand in a hardcopy in lecture (Tuesdays). Your write-up should be concise, but clear and complete!

Home Work Due date Section: Problems
1 T 9/24
  • 1.2: 3,5; 1.3: 2; 1.4: 1(aeg),2,11; 1.5:1,3,5,12,;
  • 1.3: Explain the difference between eqns.(1.3.4) and (1.3.5);
  • 2.2: 3; 2.3: 3b,4,7,8;
2 T 10/8
  • 2.4: 1(ab), 2;
  • ut = κ uxx, with u(0,t)=0, ux=± u/c at x=L, where κ, c and L are positive constants. For both problems (±): Find eigensolutions; give and justify explicit bounds on decay rates. Consider sinh(αx) solutions also. Analyze and discuss physically.
  • Derive an equation for ∫0L u2 dx for the previous problem for both boundary conditions. Analyze and discuss.
  • Solve utt = c2 uxx, with u(0,t)=0=u(L,t) and initial conditions u=f(x), ut=g(x).
  • 2.5: 1(bg), 2, 3a, 5d, 8b,
3 T 10/29
  • Read Chapter 3: Fourier Series.
  • Define piecewise smooth, even, odd
  • Let S(θ) and C(θ) be the sine and cosine series of f(θ) in 0 < θ < π, respectively
  • 3.W.:
    1. Find S(θ) and C(θ) for f(θ) = θ. Make a nice sketch (preferably with computer software) of dS/dθ and dC/dθ truncated to 2, 4, and 6 terms in the series (and more if you wish, see example of figure 3.3.8). Do these derivatives yield the sine and cosine series of df/dθ? Discuss briefly.
    2. Find S(θ) and C(θ) for f(θ) = 1 in 0 < a < θ < b < π and f(θ) = 0 otherwise. Sketch f(θ). How fast do the series converge?
    3. Find S(θ) and C(θ) for f(θ)=θ2. Sketch S(θ) and C(θ) in -2 π < θ < 2π,
    4. Sketch f(θ)=θ(1-θ/π) and find its sine and cosine series. Sketch S(θ) and C(θ) in -2 π < θ < 2π. Which series converges faster and why? Can you explain/predict a priori the convergence rates? How?
    5. Find C(θ) for f(θ)=eθ in 2 ways: (1) directly, (2) using d2eθ /dθ2 = eθ (see also problem 3.4.6).
    6. Find the sine series of f(x)=x and f(x)=x(1-x/L) in 0 <x < L.
  • 3.3.: 12, 15
  • 3.4.: 9
  • 4.4.: 3, 7, 9, 10
  • Fourier series handout and partial homework solutions
  • Is it Xmas?! All the book solutions, funded by lots and lots of commercials
T 10/22

Study Chapter 3: Fourier series convergence and differentiation. Do you understand (3.4.13)?

Read Chapter 4: Wave equation derivation

  1. from Maxwell's equations,
  2. vibrating string. Vibrating String Derivation

T 10/29

Study Chapter 5: Sturm-Liouville. What is that? Theorems? (P 157) Must know: proofs that SL operator is symmetric (`self-adjoint'), λ real, orthogonality, uniqueness of eigfcts, Rayleigh quotient.

4 T 11/12
  • 5.3.: 2,3,4,8,9. 5.4.: 1. 5.5.: 8. 5.5.A:6. 7.3. 1(a), 4(c), 7(b). 7.7.: 2(a), 4, 6.
T 11/5 Fundamental explicit example of a Sturm-Liouville EVP: Bessel's eqn and fcts .
  • Study Sec 7.7, 7.8. Where did λ go? isn't that what we are looking for?! (Sec 7.7.4)
  • Bessel functions Jm(z), Ym(z). Asymptotics as z → 0. Asymptotics as z → ∞.
R 11/7 Study how to solve heat and wave eqns in 0 ≤ r ≤ a, 0 ≤ θ < 2 π, t > 0 in terms of Fourier-Bessel series. Initial boundary value problem u(r,θ,t=0)=f(r,θ) known initial value, with u(r=a,θ,t)=0 boundary value, and u(r=0,θ,t) bounded. Essentially Haberman secs 7.7.7-9.
5 T 11/26
R 11/21
T 11/26
6 Oral T 12/2
  • Review Problems: Active learning! Flip the classroom! You discuss in class, you go to the boards. Do not hand in.