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given the matrix A =
| 1 1 0 1 4 |
| 2 0 0 4 7 |
| 1 1 1 0 5 |
| 1 -3 -1 -10 a |
determine the value of a such that, in row echelon form of A, the stairstep reaches the bottom.[/b]
I guess they mean the bottom row cannot be all zero. I had no clue how to do this so i tried reducing it to row echelon form, treating a as an unnamed contstant. No matter what i did, i never ended up with all a's in the bottom row so it seems like it wouldn't matter what a is. But the answer says a = 1.
Any ideas?
Last edited by mikau (2007-07-21 10:04:43)
A logarithm is just a misspelled algorithm.
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This is just fiddling, but I put in 1 for a and tried to solve for the 4 variables.
And I got these values: 3.5 0.5 1 0 for the variables for each column.
Don't know what this means, but hope you like it.
igloo myrtilles fourmis
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thats interesting, it may have something to do with the answer. But I don't know what.
A logarithm is just a misspelled algorithm.
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Reducing the entire matrix I get the bottom row as:
0 0 0 -16 a-1
But like you, I'm not entirely sure what "stairstep reaches the bottom" means. Though setting a to 1 would make that last column 0.
"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."
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