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In this problem, we're given the population figures in millions for the united states in 1990 by regions.
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We're also told the growth in the population in millions over the decade from 1990 to 2000.
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Our job is, assuming that the growth was the same from 2000 to 2010, what will the population be in 2010? so to set this problem up, we're using row matrices.
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We have written the population.
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By region in 1990 in the following one by four matrix, where you can think of the columns of standing for northeast, midwest, south, and west, respectively.
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And now we're going to have a second matrix.
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That's matrix a, matrix b.
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We'll represent the growth in the population in each region from 1990 to 2000.
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So those figures and millions are also given in the problem.
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So let's fill those in.
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So here's matrix b, also a one by four matrix.
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And now we don't have to write.
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What each column represents each time, but this first time through we'll do that.
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Now, we want to find the population in 2010, and we're assuming that the same growth represented by matrix b occurs again.
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So the matrix we want to calculate is a plus 2b.
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All right.
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So we have matrix a, which we will just copy over, and then we need to add twice b.
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So we'll come down here and multiply each entry in b by 2.
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That produces this new matrix.
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And i need to go back up and take out those plus signs...