MAT 461: Final Exam Review - Complex Analysis, Study notes of Mathematics

Review problems for the final exam of a complex analysis course. The problems cover various topics such as sketching sets of points, finding limits, using cauchy-riemann equations, finding harmonic conjugates, and evaluating integrals. Students are encouraged to find the roots, logarithms, and derivatives of complex numbers, and to determine the types of singularities for given functions.

Typology: Study notes

Pre 2010

Uploaded on 09/02/2009

koofers-user-cqa
koofers-user-cqa 🇺🇸

10 documents

1 / 3

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
MAT 461 - Some Review For Final
Posted December 4
These problems are meant to help supplement your studying. They will cover many, but not all of the topics
that may appear on the final.
1. Sketch the sets of points determined by the following conditions. Are these regions (open, closed or
neither), (bounded or unbounded), (connected or not connected)?
|z+ 2 i|= 2
|z3i| 3
|z1|=|zi|
2. Assuming that |z|= 1, show that
2z+ 1
z2+ 4iz
1
3. Let z= 2 2i.
Put zin exponential form.
Find z4.
Find the roots z1
2. Give the roots in principal argument form. Which is the principal root?
Find Log z(Log zhas branch cut at π).
Simplify 1
¯zinto x+iy form.
4. Let f(z) = 3z21
z(zi). Compute the following limits:
limz0f(z)
limz1f(z)
limz→∞ f(z)
5. Use the Cauchy-Riemann equations to check whether the following are analytic. (f(z) = u(x, y) +
iv(x, y)).
ln(x2+y2) + i2 tan1(y
x)
x
x2+y2+iy
x2+y2
6. Find a harmonic conjugate for x2+ 2xy2.
7. Find the derivatives of the following (assume an appropriate branch cut when necessary)
(1 + i)z2
log( 1
z)
cos1(ez)
pf3

Partial preview of the text

Download MAT 461: Final Exam Review - Complex Analysis and more Study notes Mathematics in PDF only on Docsity!

MAT 461 - Some Review For Final

Posted December 4

These problems are meant to help supplement your studying. They will cover many, but not all of the topics that may appear on the final.

  1. Sketch the sets of points determined by the following conditions. Are these regions (open, closed or neither), (bounded or unbounded), (connected or not connected)? - |z + 2 − i| = 2 - |z − 3 i| ≤ 3 - |z − 1 | = |z − i|
  2. Assuming that |z| = 1, show that (^) ∣ ∣∣ ∣

2 z + 1 z^2 + 4iz

  1. Let z = 2 − 2 i.
    • Put z in exponential form.
    • Find z^4.
    • Find the roots z 12. Give the roots in principal argument form. Which is the principal root?
    • Find Log z (Log z has branch cut at −π).
    • Simplify (^1) z ¯ into x + iy form.
  2. Let f (z) = (^) z^3 (zz^2 −−i^1 ). Compute the following limits:
    • limz→ 0 f (z)
    • limz→ 1 f (z)
    • limz→∞ f (z)
  3. Use the Cauchy-Riemann equations to check whether the following are analytic. (f (z) = u(x, y) + iv(x, y)). - ln(x^2 + y^2 ) + i2 tan−^1 ( y x ) - (^) x (^2) +xy 2 + (^) x 2 iy+y 2
  4. Find a harmonic conjugate for x^2 + 2x − y^2.
  5. Find the derivatives of the following (assume an appropriate branch cut when necessary)
    • (1 + i)z^2
    • log( (^1) z )
    • cos−^1 (ez^ )
  1. Evaluate the following integral using a parametrization for C, where C is the circle |z| = 2, positively oriented (ie. do integral as in Sec 39). (^) ∫ C

z^2 dz

  1. Let f (z) = (^) z (^21) − 1. Find Laurent Series valid for the following regions.
    • 0 < |z − 1 | < 2
    • 2 < |z − 1 | < ∞
    • 0 < |z| < 1
  2. Let C be the circle |z| = 3, positively oriented. Compute ∫ C f (z)dz for the following functions.
  • f (z) = z^2 e 1 z
  • f (z) = (^) (z (^2) +1)(zz (^2) −25)
  • f (z) = 1 z−+1ez
  • f (z) = (^) zcos− 5 zi
  • f (z) = (^) (z (^2) +4)(zz+2i)
  1. In the previous question, for each singularity inside C, what type is the singularity?
  2. There are many good book exercises to practice Chapter 7 integrals. In particular:
  • Page 257 1-
  • Page 265 1-8 (if the a’s and b’s make it too confusing, try the question with numbers plugged in for a and b)
  • Page 276 3 (use Fig 98), 4 (Fig 98), 5, 6