InterviewSolution
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यदि `A=[(3,-3,4),(2,-3,4),(0,-1,1)]` तो दिखाइए कि `A^(3)=A^(-1)` |
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Answer» `A^(2)=A.A` `=[(3,-3,4),(2,-3,4),(0,-1,1)][(3,-3,4),(2,-3,4),(0,-1,1)]` `=[(9-6+0,-9+9-4,12-12+4),(6-6+0,-6+9-4,8-12+4),(0-2+0,0+3-1,0-4+1)]` `=[(3,-4,4),(0,-1,0),(-2,2,-3)]` और `A^(4)=A^(2).A^(2)` `=[(3,-4,4),(0,-1,0),(-2,2,-3)][(3,-4,4),(0,-1,0),(-2,2,-3)]` `=[(9+0-8,-12+4+8,12+0-12),(0+-0+0,0+1+0,0+0+0),(-6+0+6,8-2-6,-8+0+9)]` `=[(1,0,0),(0,1,0),(0,0,1)]=I` `:.A^(4)=I`..............1 अब `|A|=|(3,-3,4),(2,-3,4),(0,-1,1)|` `=3|(-3,4),(-1,1)|-2|(-3,4),(-1,1)|+0` ( `C_(1)` के विस्तार) `=3(-3+4)-2(-3+4)` `=3-2=1!=0` `:.A` व्युत्क्रमणीय है `implies A^(-1)` का अस्तित्व है। समीकरण 1 से `A^(4)=I` `impliesA^(-1)A^(4)=A^(-1)I` `A^(3)=A^(-1)` |
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