Wooldridge IE AISE SSM app d

# Wooldridge IE AISE SSM app d - APPENDIX D SOLUTIONS TO...

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This edition is intended for use outside of the U.S. only, with content that may be different from the U.S. Edition. This may not be resold, copied, or distributed without the prior consent of the publisher. 122 APPENDIX D SOLUTIONS TO PROBLEMS D.1 (i) 016 21 7 2 0 61 2 180 4 5 0 5 36 24 300 ⎛⎞ −− ⎜⎟ == ⎝⎠ AB (ii) BA does not exist because B is 3 × 3 and A is 2 × 3. D.3 Using the basic rules for transpose, ( )() () ′′ = = XX X X , which is what we wanted to show. D.5 (i) The n × n matrix C is the inverse of AB if and only if C ( AB ) = I n and ( AB ) C = I n . We verify both of these equalities for C = B -1 A -1 . First, ( B -1 A -1 )( AB ) = B -1 ( A -1 A ) B = B -1 I n B = B -1 B = I n . Similarly, ( AB )( B -1 A -1 ) = A ( BB
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## This note was uploaded on 09/11/2011 for the course ECONOMICS eco375 taught by Professor Suzuki during the Spring '11 term at University of Toronto.

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