UW Common Math 308 Section 5.1.pdf - WebAssign .1(Homework...

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Current Score : 41 / 41 Due : Tuesday, November 14 2017 11:00 PM PST 1. 2/2 points | Previous Answers HoltLinAlg2 5.1.004. Find for the given matrix A. M 23 = [0, ­5, 0; 0, 5, 0; 4, 2, 2] M 31 = [­5, 6, 0; 3, ­3, 0; 2, 3, 2] Solution or Explanation 2. 2/2 points | Previous Answers HoltLinAlg2 5.1.008. Find C 13 and C 22 for the given matrix A . C 13 = 54 54 C 22 = 18 18 Solution or Explanation UW Common Math 308 Section 5.1 (Homework) KEIRA HANSEN Math 308, section F, Fall 2017 Instructor: Lucas Braune WebAssign The due date for this assignment is past. Your work can be viewed below, but no changes can be made. Important! Before you view the answer key, decide whether or not you plan to request an extension. Your Instructor may not grant you an extension if you have viewed the answer key. Automatic extensions are not granted if you have viewed the answer key. Request Extension M 23 and M 31 A = 0 5 6 0 1 3 3 0 0 5 3 0 4 2 3 2 M 23 = M 31 = 0 5 0 0 5 0 4 2 2 5 6 0 3 3 0 2 3 2 9 2 0 5 −2 −7 7 8 2 C 13 = (−1) 1+3 | M 13 | = = ( 5 )( 8 ) − ( −2 )( 7 ) = 54 C 22 = (−1) 2+2 | M 22 | = = ( 9 )( 2 ) − (0)( 7 ) = 18 5 −2 7 8 9 0 7 2
3. 4/4 points | Previous Answers HoltLinAlg2 5.1.014. Find the determinant for the given matrix A in two ways, by using cofactor expansion along the indicated row or column. (a) along the first row det( A ) = ­8 ­8 (b) along the third column det( A ) = ­8 ­8 Use the determinant to decide if is invertible. Since A is is invertible, and hence T is is invertible. Solution or Explanation A = 9 1 5 0 1 9 0 1 3 9 0 1 0 1 9 0 T ( x ) = A ( x ) det( A ) 0, det( A ) = a 11 C 11 + a 12 C 12 + a 13 C 13 + a 14 C 14
(b) Using the third column, det( A ) 0,
4. 2/2 points | Previous Answers HoltLinAlg2 5.1.030. Find all real values of a such that the given matrix is not invertible. (HINT: Think determinants, not row operations. Enter your answers as a comma­separated list. If an answer does not exist, enter DNE.) Solution or Explanation has no solutions A is invertible for all

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