Tenth Homework Set Answers

4. (a) The first few iterates are
  z0 = 0
  z1 = 0.5
  z2 = 0.75
  z3 = 1.0625
  z4 = 1.62891
  z5 = 3.15334
Because z5 is farther than 2 from the origin, c = 0.5 does not belong to the Mandelbrot set.
 
(b) The first few iterates are
  z0 = 0
  z1 = i/4
  z2 = -.0625 + .25i
  z3 = -.0586 + .2188i
  z4 = -.0444 + .2244i
  z5 = -.0484 + .2300i
  z6 = -.0506 + .2277i
The iterates appear to be converging, so we deduce c = i/4 does belong to the Mandelbrot set.
 
(c) The first few iterates are
  z0 = 0
  z1 = -5/4
  z2 = .3125
  z3 = -1.1523
  z4 = .0779
  z5 = -1.244
  z6 = .2974
Note the values appear to converge to a 2-cycle, hence do not run away to infinity. We deduce c = -5/4 does belong to the Mandelbrot set.

Return to Homework 10 Practice.