# Monthly Archives: June 2010

## Linear Algebra and Its Applications, exercise 1.4.11

Exercise 1.4.11. State whether the following statements are true or false. If a given statement is false, provide a counterexample to the statement. For two matrices A and B, if the first column of B is identical to the third … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.10

Exercise 1.4.10. Given a matrix A with entries , what are the following entries? first pivot the multiplier that is used to multiply the first row and subtract it from the ith row the value that replaces once the above … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.9

Exercise 1.4.9. Given the following two examples of FORTRAN code DO 10 I=1,N DO 10 J=1,N 10 B(I) = B(I) + A(I,J)*X(J) and DO 10 J=1,N DO 10 I=1,N 10 B(I) = B(I) + A(I,J)*X(J) Do they multiply Ax by … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.8

Exercise 1.4.8. Give non-zero examples of 3×3 matrices with the following properties: diagonal matrix ( if ); symmetric matrix ( for all ); upper triangular matrix ( if ); skew-symmetric matrix ( for all i and j). Answer: Diagonal matrix: … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.7

Exercise 1.4.7. Given the n-dimensional row vector y and column vector x, express their inner product in summation notation. Answer: We have NOTE: This continues a series of posts containing worked out exercises from the (out of print) book Linear … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.6

Exercise 1.4.6. Find the 3×2 matrix A for which . Find the 3×2 matrix B for which . Answer: We have We also have NOTE: This continues a series of posts containing worked out exercises from the (out of print) … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.5

Exercise 1.4.5. Multiply the following matrices: Considering the matrix A as a system of equations, find a solution to the system Ax = 0, for which the right-hand side of all three equations is zero. Specify whether there is just … Continue reading

## Linear Algebra and Its Applications, exercise 1.4.4

Exercise 1.4.4. Compute the number of multiplications required to multiply an mxn matrix A by an n-dimensional vector x. Also compute the number of multiplications required to multiply A by an nxp matrix B. Answer: The result of multiplying A … Continue reading

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## Linear Algebra and Its Applications, exercise 1.4.3

Exercise 1.4.3. Multiply the matrices below: Answer: The first example multiplies a 1×3 matrix by a 3×1 matrix producing a 1×1 matrix, i.e., a scalar value: As noted in the book, the result is equal to the square of the … Continue reading