Induction proof (solution included but still confused).

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Discussion Overview

The discussion revolves around a proof by induction related to a recursive function T(n), specifically examining the correctness of the base case and the induction steps. Participants are analyzing their interpretations of the problem and the provided solution, focusing on specific values of k and the implications of the definitions involved.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant confirms the correctness of the base case but expresses confusion regarding the algebraic steps in the proof, particularly when substituting k = 5.
  • Another participant corrects the first participant's interpretation of the equation, clarifying that T(2^5) should equal 3^5 - 2^6 instead of the initially stated equation.
  • A later reply indicates that the participant has encountered another issue when substituting k = 1, noting a discrepancy between their calculated value of T(2) and the expected result from the equation.
  • The same participant later identifies their mistake in the calculation related to the definition of T(n) for n > 1, specifically regarding the addition of terms.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the interpretation of the problem initially, but there is a collaborative effort to clarify misunderstandings and correct errors as they arise. The discussion remains somewhat unresolved as participants continue to identify mistakes and seek clarification.

Contextual Notes

There are limitations in the discussion regarding the assumptions made in the definitions of T(n) and the specific values of k used in the calculations. Some steps in the mathematical reasoning are not fully resolved, leading to ongoing confusion.

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Homework Statement


The problem (and its solution) is attached as Problem.jpg.


Homework Equations


Base case, induction hypothesis, and induction step.


The Attempt at a Solution


I see that the base case is correct and I also see how everything under "Proof:" is done algebraically. As I was writing this, I think I unconfused myself for some things but something must be wrong with either the way I'm interpreting this or the way the problem is because let k = 5: T(2^5) = 32 ≠ 3^(5+1) - 2^(5+1) = 3^6 - 2^6 = 665. Assuming I am wrong, what am I not seeing? Edit: I'm thinking it has something to do with the n > 1 in the definition of T(n) but I can't pin down the issue specifically.

Any input would be greatly appreciated!
Thanks in advance!
 

Attachments

  • Problem.jpg
    Problem.jpg
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The equation is T(2^5) = 3^5-2^6 not 2^5 = 3^6-2^6 :).
 
Accidentally triple posted.
 
Accidentally triple posted.
 
Oh, ya! :)

I still have another problem and it might be a similar one but I feel I'm getting close:

Let k = 1, T(1) = 1, T(2^1) = T(2) = 3*T(1) + 1 = 4

but T(2^1) = T(2) = 4 ≠ 3^2 - 2^2 = 5.

What am I doing wrong now?

Edit: Found my mistake. the +n part in the T(n) for n > 1 definition, I did +1 instead of +2 because I was doing it in my head.

Thanks for the help!
 

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