- #1
GregA
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I have to prove that for any integer n a [tex] 2^n x 2^n [/tex] grid with one square remove can be covered with L shaped tiles made up of 3 squares.
I can prove by contradiction that the number of tiles available to use is always a multiple of 3 but doing this doesn't prove that it works for L shaped tiles.
The best I can do so far is give is a set of instructions that define how you can always cover the grid with L shaped tiles:
0) get 4 square tiles and arrange them in a 2x2 square...remove one of the tiles.
1) Rename this tile as 'K' and place it with the hole at the top right
2) Place a similar tile above the first and rotate it 90 degs clockwise
3) Place a similar tile to the right of the first tile and rotate it 90 degs anticlockwise
4) Place a final similar tile diagonally opposite the first with no rotation
5) Plug the hole in the middle with a 3 square tile
6) Call this tile K + 1 and then proceed to step 1
Does this count as proof by induction?
I can prove by contradiction that the number of tiles available to use is always a multiple of 3 but doing this doesn't prove that it works for L shaped tiles.
The best I can do so far is give is a set of instructions that define how you can always cover the grid with L shaped tiles:
0) get 4 square tiles and arrange them in a 2x2 square...remove one of the tiles.
1) Rename this tile as 'K' and place it with the hole at the top right
2) Place a similar tile above the first and rotate it 90 degs clockwise
3) Place a similar tile to the right of the first tile and rotate it 90 degs anticlockwise
4) Place a final similar tile diagonally opposite the first with no rotation
5) Plug the hole in the middle with a 3 square tile
6) Call this tile K + 1 and then proceed to step 1
Does this count as proof by induction?
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