MATH 551

Complex Analysis

  • Class Meets: 2:10-3:00 MWF in Wilson 1-148
  • Instructor:
    Curt Vogel
    2-210 Wilson Hall
    ph. 994-5332
    E-mail: vogel@math.montana.edu
    Home Page: www.math.montana.edu/~vogel
  • Textbook:
    Complex Analysis, 4th Edition, by Serge Lang, published by Springer-Verlag, 1999.
  • Course Outline:
    Hopefully we'll cover material in the textbook up through Chapter 6.
  • Grading:
    Homework ------ 30%
    Midterm Exam --- 30%
    Final Exam ----- 40%

    The final exam is scheduled for 8-9:50 am, Thurs, May 8, 2003. Students are strongly encouraged to work together on homework assignments. Late homework will be accepted only with the advanced permission of the instructor.

  • Homework for 1/22/03:
    Sect I.1. #3, 6 (due 1/24/03); #1abc, 2ace, 8, 9 (recommended)
    Sect I.2. #3, 9 (due 1/24/03); #1abcf, 2abfg, 4, 10a, 11, 13 (recommended)
    Sect I.3. #1, 2 (due 1/27/03); #3, 4 (recommended)
  • Homework for 1/27/03:
    Sect I.6. Prove that if a mapping F is Frechet differentiable, then it is Gateaux differentiable.
    In addition, show that DF(x;p) = F'(x)p. (due 1/31/03)
  • Homework for 1/29/03, due 2/3/03:
    Show that f(z) = conj(z) is nowhere differentiable, using (i) the definition of complex differentiability; and (ii) the Cauchy-Riemann equations.
    Let f be holomorphic in a set S. Show that if f'(z) = 0 in S, then f is constant in S.
  • Homework for 1/31/03:
    Sect II.1. #1g, 3 (due 2/7/03); #1acf, 6 (recommended)
  • Homework for 2/3/03:
    Prove, via a simple counter example, that C[a,b] is not complete with respect to the L-2 norm. (due 2/7/03)
    Prove that C[a,b] is complete with respect to the L-infinity, or sup, norm. Also, prove that C(R) is not complete with respect to the L-infinity norm. (recommended for math students)
  • Homework for 2/5/03:
    Provide a rigorous proof of the ratio test (recommended for math students), making use of comparison with a geometric series.
  • Homework for 2/21/03:
    Sect III.2, exercises 1,2,5,9,11 (due 2/26/03); exercises 3,4,7 (recommended).
    Provide a rigorous proof of the Fundamental Theorem of Calculus (due 2/26/03).
  • Midterm Takehome Exam, due 3/7/03
    PDF version
    Postscript version
  • Comment on Problem 6 of the Midterm Takehome Exam: The key result that you need is Theorem 7.1 (Cauchy formula on a disk) on p. 126 of the text. This result holds for a disk centered at z0 (which you can take to be 0) for ***any*** radius r, since f is assumed to be holomorphic on all of the complex plane. To get the needed formulas for the derivatives, you can either (i) repeatedly differentiate the Cauchy formula; or (ii) expand 1/(w-z) as a geometric series as on p. 128, interchange integration and summation to get the expression at the bottom of p. 128, and relate the coefficients of the power series to derivatives of f evaluated at z0. Once you have a Cauchy-like derivative formula, proceed as in Monday's class notes.
    Homework for Friday, 3/21/03: Work out the details of both approaches (i) and (ii). I know that some of you already did this for approach (ii) in Problem 3. If this is the case, please recopy the relevant material and hand it in together with part (i).
  • Homework for 4/2/03:
    PDF version
    Postscript version
  • Homework for 4/11/03:
    Section V.2, p. 163: Exercises 1,2,3,4,5a,8,13.
    Section V.3, p. 170: Exercises 1ab,2,5,6,9. Recommended: #10.
  • Homework for 4/21/03:
    Section VI.1, p. 186: Exercises 18,19
    Section VI.2, p. 204: Exercises 1a,5ab,10,11,14a,18
    Use Laplace transforms & the Bromwich inversion formula to solve the ODE IVP u'(t) - u(t) = sin(t), t>0; u(0)=2.
    Carefully explain what happens, in the limit, to all the contour integral terms. You will first need to show that the Laplace transform of sin(t) is 1/(s^2 + 1).
  • Homework for 5/2/03:
    PDF version
    Postscript version