MC 36
Fall 1998
Problem Set 6
Due 11/4/98, 17:33
 
  1. Grimaldi 4.2: 14
  2. Grimaldi 4.2:  18
  3. Grimaldi 4.3:  14
  4. Grimaldi 4.4:  4
  5. Let a1, a2, a3, ... be the sequence defined by a1 = 1 and, for n >1, an = 2 an-1+1.  Write down the first six terms of this sequence.  Guess a formula for a_n and prove that your guess is correct.
  6. (a)  Find integers s and t such that 17,369s + 5,472t=1.  (b)  Find integers s and t such that $17,369s + 5,472t=4.
  7. Decrypt the following message which was was encrypted using the function f(p)=11p+3 mod 26.
    N CDAV D MIBBG OPE ECV FDIRNQ NT EBB TFDUU.