Math Problem Statement
Find a solution to the following divide-and-conquer recurrence relations. You may use any method.
For all problems, assume that T(1) = 1.
(1) (Home Work) T(n) = 3T(n/2) + n lg n.
T(1) = 1, T(n) = 3T(n/2) + n log n
let n = 2^k, k = 0,1,2,3,...,infinity
T(2^k) = 3T((2^K)/2) + 2^K (log{2^k})
= 3T(2^{k-1}) + 2k^2 (k) (log{2})
= 3T(2^{k-1}) + k2^k
3T(2^k) - T(2^{k-1}) = k2^k
(x-1)(x-2) = 0
r_1 = 1, r_2 =2
general solution: T(2^k) = c_1 + A(2^k)
finding constants from boundary conditions
k = 0 => T(2^0) = T(1) = 1
k = 1 => T(2^1) = 3T(1) + 2 (log(2)) = 5
k = 0 => c_1 + A(2^0) = 1
k = 1 => c_1 + A(2^1) = 5
solving for the constants c_1 = -3, A = 4
T(2^k) = -3 + 4(2^k)
since n=2^k => k = log_2{n}
T(n) = -3+4(2^{log_2 n})
is it correct? if not then correct it
Solution
The initial approach has a few issues, so let's work through the problem carefully to verify and correct it.
Given: with .
We will use the recurrence relation and the Master Theorem to solve this.
Step 1: Verify Applicability of the Master Theorem
For the recurrence relation , we have:
- ,
- , and
- .
-
Calculate : Thus, .
-
Compare with :
- grows more slowly than because .
- Therefore, for some .
Since grows more slowly than , by the Master Theorem, the solution to this recurrence relation is:
Final Answer
where .
This is the asymptotic solution to the recurrence relation.
Would you like a detailed breakdown of each calculation or have further questions?
Related Problems
- Solve the recurrence .
- Find the solution for .
- Solve using the Master Theorem.
- Determine the solution to .
- Use the recursion tree method to solve .
Tip
For divide-and-conquer recurrences, start by identifying , , and terms to quickly assess whether the Master Theorem applies.
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Math Problem Analysis
Mathematical Concepts
Recurrence Relations
Divide and Conquer
Asymptotic Analysis
Formulas
Master Theorem
T(n) = aT(n/b) + f(n)
Theorems
Master Theorem
Suitable Grade Level
Grades 11-12