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3 and 4 .Determinants and Matrices
medium
यदि $A$ और $B$ दो आव्यूह इस प्रकार हैं कि $AB = B$ और $BA = A,$ तो ${A^2} + {B^2} = $
A
$2AB$
B
$2BA$
C
$A + B$
D
$AB$
Solution
दिया गया है, $AB = B$तथा $BA = A$
इसलिये ${A^2} + {B^2} = AA + BB = A(BA) + B(AB)$
$ = (AB)A + (BA)B = BA + AB = A + B$,
$(\because \,\,AB = B$ और $BA = A)$.
Standard 12
Mathematics