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10. LU decomposition using Crout's method of matrix example ( Enter your problem )
  1. Example `[[8,-6,2],[-6,7,-4],[2,-4,3]]`
  2. Example `[[3,2,4],[2,0,2],[4,2,3]]`
  3. Example `[[1,1,1],[-1,-3,-3],[2,4,4]]`
  4. Example `[[2,3],[4,10]]`

1. Example `[[8,-6,2],[-6,7,-4],[2,-4,3]]`





1. Find LU decomposition using Crout's method of Matrix ...
`[[8,-6,2],[-6,7,-4],[2,-4,3]]`


Solution:
Crout's method for LU decomposition
Let `A=LU`

`8``-6``2`
`-6``7``-4`
`2``-4``3`
 = 
`l_(11)``0``0`
`l_(21)``l_(22)``0`
`l_(31)``l_(32)``l_(33)`
 `xx` 
`1``u_(12)``u_(13)`
`0``1``u_(23)`
`0``0``1`


`8``-6``2`
`-6``7``-4`
`2``-4``3`
 = 
`l_(11)``l_(11)u_(12)``l_(11)u_(13)`
`l_(21)``l_(21)u_(12) + l_(22)``l_(21)u_(13) + l_(22)u_(23)`
`l_(31)``l_(31)u_(12) + l_(32)``l_(31)u_(13) + l_(32)u_(23) + l_(33)`


This implies
`l_(11)=8`

`l_(11)u_(12)=-6=>8xxu_(12)=-6=>u_(12)=-0.75`

`l_(11)u_(13)=2=>8xxu_(13)=2=>u_(13)=0.25`



`l_(21)=-6`

`l_(21)u_(12) + l_(22)=7=>(-6)xx(-0.75) + l_(22)=7=>l_(22)=2.5`

`l_(21)u_(13) + l_(22)u_(23)=-4=>(-6)xx0.25 + 2.5xxu_(23)=-4=>u_(23)=-1`



`l_(31)=2`

`l_(31)u_(12) + l_(32)=-4=>2xx(-0.75) + l_(32)=-4=>l_(32)=-2.5`

`l_(31)u_(13) + l_(32)u_(23) + l_(33)=3=>2xx0.25 + (-2.5)xx(-1) + l_(33)=3=>l_(33)=0`



Now checking `A=LU` ?

`LU` = 
`8``0``0`
`-6``2.5``0`
`2``-2.5``0`
 `xx` 
`1``-0.75``0.25`
`0``1``-1`
`0``0``1`
 = 
`8``-6``2`
`-6``7``-4`
`2``-4``3`


And `A` = 
`8``-6``2`
`-6``7``-4`
`2``-4``3`


Solution is possible.




This material is intended as a summary. Use your textbook for detail explanation.
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