Induction Proof for A^n = 1 2^nProve your formula by mathematical induction.

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The discussion revolves around proving the formula A^n = [1, 2n; 0, 1] using mathematical induction. Participants clarify the induction process, emphasizing the need to establish a base case, assume the proposition for k, and prove it for k + 1. The matrix A is defined as [1, 2; 0, 1], and as n increases, the value in the matrix's second column increases by 2 for each successive power. The conversation highlights the importance of recognizing patterns in matrix powers and constructing a clear inductive proof. Ultimately, participants work towards formulating a coherent proof based on their observations.
  • #31
@Robb, as already mentioned, for an induction proof you need to
  1. Establish a base case (e.g., with n = 1).
  2. Assume that the proposition is true if n = k.
  3. Show that if the proposition is true for n = k, it must also be true for n = k + 1.
The base case is trivial in this problem.
For step 2, it's reasonable to assume that for n = k, ##A^k = \begin{bmatrix} 1 & 2k \\ 0 & 1\end{bmatrix}##
For step 3, show, using the assumption in step 2, that ##A^{k + 1} = \begin{bmatrix} 1 & 2(k + 1) \\ 0 & 1\end{bmatrix}##
Your work should start with ##A^{k + 1} = \dots##.
That's it!
 
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  • #32
Mark44 said:
@Robb, as already mentioned, for an induction proof you need to
  1. Establish a base case (e.g., with n = 1).
  2. Assume that the proposition is true if n = k.
  3. Show that if the proposition is true for n = k, it must also be true for n = k + 1.
The base case is trivial in this problem.
For step 2, it's reasonable to assume that for n = k, ##A^k = \begin{bmatrix} 1 & 2k \\ 0 & 1\end{bmatrix}##
For step 3, show, using the assumption in step 2, that ##A^{k + 1} = \begin{bmatrix} 1 & 2(k + 1) \\ 0 & 1\end{bmatrix}##
Your work should start with ##A^{k + 1} = \dots##.
That's it!

Now that makes sense! As always, the help is much appreciated!
 

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