If D=diag(d1,d2,d3,.....,dn) where di≠0 for all i=1,2,......,n ,be a diagonal matrix ,then D−1 is equal to

let  D=diag(d1,d2,d3,.....,dn)  then |D|=d1d2.....dn cofactor   of   d1=d2d3.....dn cofactor   of   d1=d2d3.....dn cofactor  dn=d1d2.....dn−1 Aslo   Dij=0   if  i≠j now    D−1=adj D|D| =diag(d2d3.....dn,....,d1d2.....dn−1)d1d2.....dn =diag(d1−1d2−1.....dn−1)