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Q29E

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Linear Algebra With Applications
Found in: Page 307
Linear Algebra With Applications

Linear Algebra With Applications

Book edition 5th
Author(s) Otto Bretscher
Pages 442 pages
ISBN 9780321796974

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Short Answer

In an economics text 11we find the following system:

[-R1R1-1-αα1-α-1-α2R2-R2-1-α2α][dx1dy1dp]=[00-R2de2] .

Solve for dx1,dy1, and dp. In your answer, you may refer to the determinant of the coefficient matrix as D. (You need not compute D.) The quantities R1,R2 and D are positive, and a is between zero and one. If de2 is positive, what can you say about the signs of dy1 and dp?

Therefore,

dx1dy1dp=R2de2R1-11-ααDR2de2R1-R1α+α1-αDR1R2de2D

If R1R2and Dare positive, α is between 0 and 1, and de2 is positive, then dy2and are also positive.

See the step by step solution

Step by Step Solution

Step 1: Definition. 

In matrices, Cramer's rule expresses the solution in terms of the determinants of the coefficient matrix (i.e., for a square matrix) and of matrices obtained from it by replacing one column by the column vector of right-hand-sides of the equations.

Step 2: To solve dx1,dy1and dp

Let,

[-R1R1-(1-α)α1-α-(1-α)2R2-R2-(1-α)2α]

Now, using Cramer's rule, we solve:

dx1=0R1-1-α01-α-1-α2-R2de2-R2-1-α2αDdx1=R2de2(R1-1)1-α2Ddy1=-R10-1-αR20-1-α2R2-R2de2-1-α2αDdy1=R2de2R1-R1α+α1-αDdp=-R1R10α1-α0R2-R2-R2de2Ddp=R1R2de2D

dx1dy1dp=R2de2R1-11-ααDR2de2R1-R1α+α1-αDR1R2de2D

Step 3: If de2 is positive, what can you say about the signs of dy1 and dp

If R1,R2 and D are positive, α is between 0 and 1 and de2 is positive, then dy2 and dp are also positive.

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