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Ay. ay. ay (Posted on 2023-04-23) Difficulty: 1 of 5
y=sqrt(i*sqrt(i*sqrt(i... ...)))

Evaluate y.

No Solution Yet Submitted by Ady TZIDON    
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Solution computer approach Comment 3 of 3 |
i= 1i; y=8+3i;
for l=1:35
  y=sqrt(i*y);
  fprintf('%4d, %10.8f+%10.8fi\n',l,real(y),imag(y))
 end
y

shows that even when the "rightmost" (starting) value is a complex number 8+3*i, the iteration converges to i.

    iteration #          value
              1, 1.66493299+2.40249909i
              2, 0.51015375+1.63179531i
              3, 0.19734077+1.29257057i
              4, 0.08653768+1.14020145i
              5, 0.04049230+1.06856964i
              6, 0.01958227+1.03390188i
              7, 0.00962884+1.01685525i
              8, 0.00477430+1.00840371i
              9, 0.00237717+1.00419588i
             10, 0.00118610+1.00209644i
             11, 0.00059243+1.00104785i
             12, 0.00029606+1.00052383i
             13, 0.00014799+1.00026189i
             14, 0.00007399+1.00013094i
             15, 0.00003699+1.00006547i
             16, 0.00001849+1.00003273i
             17, 0.00000925+1.00001637i
             18, 0.00000462+1.00000818i
             19, 0.00000231+1.00000409i
             20, 0.00000116+1.00000205i
             21, 0.00000058+1.00000102i
             22, 0.00000029+1.00000051i
             23, 0.00000014+1.00000026i
             24, 0.00000007+1.00000013i
             25, 0.00000004+1.00000006i
             26, 0.00000002+1.00000003i
             27, 0.00000001+1.00000002i
             28, 0.00000000+1.00000001i
             29, 0.00000000+1.00000000i
             30, 0.00000000+1.00000000i
             31, 0.00000000+1.00000000i
             32, 0.00000000+1.00000000i
             33, 0.00000000+1.00000000i
             34, 0.00000000+1.00000000i
             35, 0.00000000+1.00000000i
             
To be more exact as to the value after 35 iterations, it's

y =
       3.52745892188977e-11 +      1.00000000006243i

  Posted by Charlie on 2023-04-23 11:09:09
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