Q17 of 74 Page 7

If , verify that A2 – 4 A + I = O, where and . Hence, find A – 1.

A2 =


=


4A =


I =


Now, A2 – 4 A + I =


=


Hence, =


Now, A2 – 4 A + I = 0


A.A – 4A = – I


Multiply by A – 1 both sides


A.A(A – 1) – 4A A – 1 = – IA – 1


AI – 4I = – A – 1


A – 1 = 4I – A =


A – 1 =


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