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Let A be a squarre matrix of order of order 3 satisfies the matrix equation `A^(3) -6 A ^(2) + 7 A - 8 I = O and B = A- 2 I . ` Also, `det A = 8.` If `adj((B/2)^(-1))= (p/q)B`, where `p,q in N` , the least valuse of `(p+q)` is equal toA. 7B. 9C. 29D. 41 |
Answer» Correct Answer - A `because B = A -2I ` `therefore A^(-1) B = I - 2A^(-1)` ...(i) `adj[(B/2)^(-1)]= (B/2)/abs(B/2) = (B/2)/(1/8abs(B)) = (4B)/abs(B) = 4/10 B [because abs(B) = 10 ]` `= 2/5 B = p/q B` [given] `therefore p= 2 and q = 5 ` Hence, p + q = 7 |
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