document.write( "Question 912367: show that A(adj A)= (adj A)A=(adj A)I \n" ); document.write( "
Algebra.Com's Answer #553776 by rothauserc(4718)![]() ![]() You can put this solution on YOUR website! I assume that A is a square matrix, then we know \n" ); document.write( "The inverse of A = adj(A) / det(A) where det is the determinant \n" ); document.write( "multiply both sides of the = by A and we get \n" ); document.write( "A*inverse of A = (A*adj(A)) / det(A) and A*inverse of A = (adj(A)*A) / det(A) \n" ); document.write( "note that * means multiply \n" ); document.write( "the above implies that \n" ); document.write( "I = (A*adj(A)) / det(A) and I = (adj(A)*A) / det(A) \n" ); document.write( "From above, we can say that det(A)I = A*adj(A) and det(A)I = adj(A)*A, then \n" ); document.write( "A*adj(A) = adj(A)*A= det(A)*I \n" ); document.write( " \n" ); document.write( " |