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Determine the condition number of the following matrices. Comment on whether or not small errors in data of each matrix A can result in large errors in the solution of Ax=b.

[1 3]
[ ]
[2 4]

User Endre Simo
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Final answer:

The question involves determining the condition number of a matrix to assess how sensitive the solution of Ax=b is to changes in A or b. Assuming the matrix A is [[1,3],[2,4]], we would calculate its inverse, determine the norms of A and its inverse, and multiply them to find the condition number. A high condition number indicates sensitivity to small errors; a low one suggests stability against such errors.

Step-by-step explanation:

The question relates to the condition number of a matrix, which is a measure of how sensitive the solution of the linear system Ax=b is to changes in the matrix A or the vector b. To determine the condition number, we typically need the matrix A and its inverse. However, the matrix provided in the question seems to be incomplete. Assuming the correct matrix is A = [[1,3],[2,4]], we first need to calculate its inverse, provided it exists, and then use the norm of both A and its inverse to find the condition number.

The formula for the condition number k(A) of the matrix A in the context of the Euclidean norm is k(A) = ||A|| * ||A-1||, where ||...|| denotes the matrix norm. For a 2x2 matrix A = [[a,b],[c,d]], the inverse A-1 is given by (1/det(A)) * [[d,-b],[-c,a]]. The determinant of A, det(A), is ad - bc. If det(A) is nonzero, the matrix is invertible; otherwise, it is singular, and the condition number is undefined. For the matrix A = [[1,3],[2,4]], the determinant is (1)(4) - (2)(3) = 4 - 6 = -2, which is nonzero, hence the matrix is invertible. The inverse of A is (1/-2) * [[4,-3],[-2,1]] = [[-2,1.5],[1,-0.5]]. We then calculate the norms of A and A-1 and multiply them to get the condition number. Generally, a high condition number indicates that the system is sensitive to small errors in data, while a low condition number implies the opposite.

User Max Ehrlich
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