Question: 2. (20 POINTS) There are times when you can correctly guess an asymptotic bound as the solution of a recurrence, but the math may still

 2. (20 POINTS) There are times when you can correctly guess

2. (20 POINTS) There are times when you can correctly guess an asymptotic bound as the solution of a recurrence, but the math may still not work in induction. As an example, given the recurrence T(n) = Tn/2) +T (n/2) + 1. We guess that the solution is O(n), and we try to show that T(n) son for an appropriate choice of the constant c. Substituting our guess in the recurrence, we obtain: T(n): cn/2) + cn/2 + 1 son +1 which does not imply T(n) s cn for any choice of c. In order to prove our original guess, i.e. the solution is O(n), we must make a stronger inductive hypothesis: Subtract a lower order term (which is d for this example) from our previous guess, such that the new guess becomes Tin) scn-d, where bois constant. We now have Tin) s (cn/2 - d) + (cn/2 - d) + 1 son - 2d + 1 scn-d For d = 1, we have proven that T(n) is O(n). Using the information provided above, now consider the recurrence relation T(n) = 4T(n /3) +n to answer the following questions: 2.A.) (10 POINTS) Use the substitution method to show that the attempt to prove the guessed solution for T(n) is (nlog34) fails. Please show your work. 2.B.) (10 POINTS) Now, try subtracting a lower order term (which is dn for this question) from the guess so that the substitution proof work, i.e. Tin) is (nlog34) Also remember that solving recurrences will yield: Asymptotic tight bound "O", if the recurrence is in the form T(n) = aT(n/b) + f(n) Asymptotic upper bound "O", if the recurrence is in the form T(n) s aT(n/b) + f(n) Asymptotic lower bound "O", if the recurrence is in the form T(n) 2 aT(n/b) + f(n)

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