Matrices and Determinants - StudentOfFortune.com

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lcortina
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$1.00 Matrices and Determinants

From Mathematics: Algebra
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Due on Dec. 09, 2008
Asked on Dec. 08, 2008 at 10:14:21AM

Q:
Problem: A survey of 615 teenagers found that 44% of the boys and 35% of the girls would like to be taller. Altogether, 231 teenagers in the survey wished they were taller.

(1)Set up a system of equations to model this scenario.

(2)Use determinants and Cramers rule to determine how many boys and how many girls were in the survey.

(3)Answer the question in (2) by using inverse matrice

(4)Compare the two methods. When might one method be better than another method for solving a system?

1)Part 2: Write a 250 word summary of the above problem. Your written work should include but necessarily be limited to the following; an explanation of the problem, a review of the mathematical concepts involved, a critique of the method used to obtain the solution, and an interpretation of the answer.

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Posted by:

geniusy_2006

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$5.00 Here is the answer for Q.1

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Posted on Dec. 08, 2008 at 10:29:44AM

A:
Preview: ... olutio ...

The full tutorial is about 6 words long plus attachments.

Attachments:
icortina_matrix.doc (24K) (Preview)

Posted by:

alephzero314
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Posted on Dec. 08, 2008 at 11:03:45AM

A:
Preview: ... is: x + y = 615 0.44x + 0.35y = 231 In matrix form, this would be Ax=b, where A is the matrix 1 1 .44 .35 and b is the vector (615,231), and x is the vector (x y). Let A1 be the matrix A with the first column of A replaced by the column b. Let A2 be the matrix A with the second column of A replaced by the column b. Then Cramer's rule says: x = det(A1)/det(A) y = det(A2)/det(A) det(A) = 1(.35)-1(.44) = -.09 A1 is the matrix 615 1 231 .35 det(A1) = 615*0.35-231*1 = -15.75 A2 is the matrix 1 615 .44 231 det(A2) = 1(231)-.44*615 = -39.6 So by Cramer's Ru ...

The full tutorial is about 567 words long .