(i) If A=[3√32420] and B=[2−12124], verify that (A′)′=A. (ii) If A=[3√32420] and B=[2−12124], verify that (A+B)′=A′+B′. (iii) If A=[3√32420] and B=[2−12124], verify that (kB)′=(kB′) where k is any constant.
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Solution
(i) Given: A=[3√32420]
To verify: (A′)′=A A′=[3√32420]′=⎡⎢⎣34√3220⎤⎥⎦ (A′)′=⎡⎢⎣34√3220⎤⎥⎦′=[3√32420]=A
Thus, (A′)=A
(ii) Given: A=[3√32420] and B=[2−12124]
To verify: (A+B)′=A′+B′
Solving L.H.S. (A+B)=[3√32420]+[2−12124] ⇒(A+B)=[3+2√3+(−1)2+24+12+20+4] ⇒(A+B)=[5√3−14544]
Thus, (A+B)′=⎡⎢⎣55√3−1444⎤⎥⎦
A=[3√32420] and B=[2−12124]
Solving R.H.S. A′+B′=⎡⎢⎣34√3220⎤⎥⎦+⎡⎢⎣21−1224⎤⎥⎦ ⇒A′+B′=⎡⎢⎣3+24+1√3+(−1)2+22+20+4⎤⎥⎦ ⇒A′+B′=⎡⎢⎣55√3+(−1)444⎤⎥⎦
So, L.H.S.=R.H.S.
Thus, (A+B)′=A′+B′
(iii)A=[3√32420] and B=[2−12124]
To verify: (kB)′=(kB′),k is any constant. B=[2−12124] ⇒kB=[2k−k2kk2k4k] ⇒(kB)′=⎡⎢⎣2k2k−k2k2k4k⎤⎥⎦=k⎡⎢⎣21−1224⎤⎥⎦=kB′
Hence, verified.