2. Find A/B ...
A=[[2,3,1],[0,5,6],[1,1,2]],B=[[2,1,-1],[1,0,-1],[1,1,2]]Solution:=2 xx (0 × 2 - (-1) × 1) -1 xx (1 × 2 - (-1) × 1) -1 xx (1 × 1 - 0 × 1)=2 xx (0 +1) -1 xx (2 +1) -1 xx (1 +0)=2 xx (1) -1 xx (3) -1 xx (1)= 2 -3 -1=-2 = | | +(0 × 2 - (-1) × 1) | -(1 × 2 - (-1) × 1) | +(1 × 1 - 0 × 1) | | | -(1 × 2 - (-1) × 1) | +(2 × 2 - (-1) × 1) | -(2 × 1 - 1 × 1) | | | +(1 × (-1) - (-1) × 0) | -(2 × (-1) - (-1) × 1) | +(2 × 0 - 1 × 1) | |
| T |
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= | | +(0 +1) | -(2 +1) | +(1 +0) | | | -(2 +1) | +(4 +1) | -(2 -1) | | | +(-1 +0) | -(-2 +1) | +(0 -1) | |
| T |
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"Now, "B^(-1)=1/|B| × Adj(B) = | | -0.5 | 1.5 | 0.5 | | | 1.5 | -2.5 | -0.5 | | | -0.5 | 0.5 | 0.5 | |
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A×(B^(-1)) | = | | × | | -0.5 | 1.5 | 0.5 | | | 1.5 | -2.5 | -0.5 | | | -0.5 | 0.5 | 0.5 | |
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= | | 2×-0.5+3×1.5+1×-0.5 | 2×1.5+3×-2.5+1×0.5 | 2×0.5+3×-0.5+1×0.5 | | | 0×-0.5+5×1.5+6×-0.5 | 0×1.5+5×-2.5+6×0.5 | 0×0.5+5×-0.5+6×0.5 | | | 1×-0.5+1×1.5+2×-0.5 | 1×1.5+1×-2.5+2×0.5 | 1×0.5+1×-0.5+2×0.5 | |
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= | | -1+4.5-0.5 | 3-7.5+0.5 | 1-1.5+0.5 | | | 0+7.5-3 | 0-12.5+3 | 0-2.5+3 | | | -0.5+1.5-1 | 1.5-2.5+1 | 0.5-0.5+1 | |
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This material is intended as a summary. Use your textbook for detail explanation.
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