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If `A=[(1,2),(2,1)]` and `f(x)=(1+x)/(1-x)`, then f(A) isA. `[[1 ,1],[1,1]]`B. `[[2 ,2],[2,2]]`C. `[[-1 ,-1],[-1,-1]]`D. None of these |
Answer» Correct Answer - C `because f(x) = (1+x)/(1-x)` `rArr (1-x) f(x) = 1 +x` `rArr (I-A)f(A) = (I+A)` ` rArr f(A) = (I-A)^(-1) (I+A)` `([[1,0],[0,1]]-[[1,2],[2,1]])^(-1)([[1,0],[0,1]]+[[1,2],[2,1]])` `[[0,-2],[-2,0]]^(-1)[[2,2],[2,2]]=-1/4[[0,2],[2,0]][[2,2],[2,2]]` `=-1/4 [[4,4],[4,4]]=[[-1,-1],[-1,-1]]` |
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