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Let `Ad nB`be `3xx3`matrtices of ral numbers, where `A`is symmetric, `"B"`is skew-symmetric , and `(A+B)(A-B)=(A-B)(A+B)dot`If `(A B)^t=(-1)^k A B ,w h e r e(A B)^t`is the transpose of the mattix `A B ,`then find the possible values of `kdot` |
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Answer» Correct Answer - B::D `because A^(t) = A, B^(t) = -B` Given, `(A+B) (A-B) = (A-B) (A+B) ` `rArrA^(2) - AB + BA-B^(2) = A^(2) + AB - BA-B^(2)` `rArr AB= BA` Also, given `(AB)^(t)=(-1)^(k)AB` `rArr B^(t) A^(t) = (-1)^(k) AB` `rArr -BA = (-1)^(k) AB` `rArr (-1) = (-1)^(k) [because AB= BA]` `therefore k = 1, 3, 5, ...` |
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