1.

यदि `A=[(1,2,3),(3,-2,1),(4,2,1)]` तो दर्शाइए कि `A^(3)-23A-40I=O`

Answer» `A^(2)=A.A=[(1,2,3),(3,-2,1),(4,2,1)][(1,2,3),(3,-2,1),(4,2,1)]`
`=[(1+6+12,2-4+6,3+2+3),(3-6+4,6+4+2,9-2+1),(4+6+4,8-4+2,12+2+1)]`
`=[(19,4,8),(1,12,8),(14,6,15)]`
`A^(3)=A.A^(2)=[(1,2,3),(3,-2,1),(4,2,1)]=[(19,4,8),(1,12,8),(14,6,15)]`
`=[(19+2+42,4+24+18,8+16+45),(57-2+14,12-24+6,24-16+15),(76+2+14,16+24+6,32+16+15)]`
`=[(63,46,69),(69,-6,23),(92,46,63)]`
`40I=40[(1,0,0),(0,1,0),(0,0,1)]=[(40,0,0),(0,40,0),(0,0,40)]`
`:.A^(3)-23A-40I`
`=[(63,46,69),(69,-6,23),(92,46,63)]-23[(1,2,3),(3,-2,1),(4,2,1)]-[(40,0,0),(0,40,0),(0,0,40)]`
`[(63,46,69),(69,-6,23),(92,46,63)]+[(-23,-46,-69),(-69,46,-23),(-92,-46,-23)]`
`+[(-40,0,0),(0,-40,0),(0,0,-40)]`
`=[(63-23-40.46-46+0,69-69+0),(69-69+0,-6+46-40,23-23+0),(92-92+0,46-46+0,63-23-40)]`
`=[(0,0,0),(0,0,0),(0,0,0)]=O`
अत: `A^(3)-23A-40I=O`


Discussion

No Comment Found

Related InterviewSolutions