document.write( "Question 40403: Proof of Hermitian matrices: If A and B are Hermitian matrices, I need to show that BA = AB iff AB is Hermitian, but I can't figure out how... \n" ); document.write( "
Algebra.Com's Answer #26156 by venugopalramana(3286)![]() ![]() You can put this solution on YOUR website! A AND B ARE COMPLEX HERMITIAN MATRICES OF ORDER (N,N) \n" ); document.write( "LET TRANSPOSE OF A AND B BE A' AND B' \n" ); document.write( "SINCE A,B ARE HERMITIAN,WE HAVE \n" ); document.write( "A=CONJUGATE (A') AND B= CONJ(B') .I \n" ); document.write( "CASE 1. \n" ); document.write( "AB IS HERMITIAN.LET AB=C ..SO AB=C=CONJ(C')=CONJ(AB)' ..II \n" ); document.write( "C'=(AB)'=B'A' \n" ); document.write( "CONJ(C')=CONJ(B'A')=CONJ(B')CONJ(A')=BA FROM I \n" ); document.write( "BUT AB=CONJ(C') FROM II \n" ); document.write( "SO AB=BA \n" ); document.write( "CASE 2. \n" ); document.write( "AB=BA= CONJ(B')CONJ(A')=CONJ(B'A')=CONJ(AB)'=AB .. \n" ); document.write( "HENCE AB IS HERMITIAN. \n" ); document.write( " |