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If `A=[(0,x),(y,0)]` and `A^(3)+A=O` then sum of possible values of xy is |
Answer» Correct Answer - B `A^(3)+A=O` `implies A(A^(2)+I)=O` `implies |A(A^(2)+I)|=0` `implies |A|=0` or `|A^(2)+I|=0` If `|A|=0`, then `xy=0` `A^(2)+I=[(0,x),(y,0)][(0,x),(y,0)]+[(1,0),(0,1)]` `=[(xy,0),(0,xy)]+[(1,0),(0,1)]` `=[(xy+1,0),(0,xy+1)]` `|A^(2)+I|=0` `implies (xy+1)^(2)=0` `implies xy=-1` So, sum of possible values of `xy` is `-1`. |
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