Suppose that A B C D are square matrices and I is the identi
Suppose that A, B, C, D are square matrices and I is the identity matrix of the same size.
(a) Show that if AB = AC and DA = I, then B = C.
(b) Show that if AC = BC and CD = I, then A = B.
(c) Show that if AB = I and CA = I, then B = C.
Solution
(c) Show that if AB = I and CA = I, then B = C.
given AB= I
so B=A-1....................(i)
given CA=I
so C=A-1....................(ii)
from (i),(ii)
we can say that B=C
therefore B=C
