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Findug Least Square Solutions

  • Thread starter Punkyc7
  • Start date
  • #1
420
0
Find the least square solutions x* of the system Ax=b


A=[1 3
2 6]

b=[5
0]


A^tAx=A^tb


So I get down to
[5 15 [x1 [5
15 45] x2] = 15]

so i get [1
0]

The book says the solution is
[1-3s
s]

not sure were that came from
 
Last edited:

Answers and Replies

  • #2
lanedance
Homework Helper
3,304
2
can you explain your method?
 
  • #3
420
0
Just plug into the formula the only problem is that the matrix I get by multiplying A transpose A cannot not be inverted
 
  • #4
hotvette
Homework Helper
996
5
Just plug into the formula the only problem is that the matrix I get by multiplying A transpose A cannot not be inverted
That's because ATA is singular, which in this case means an infinite number of solutions. If you multiply things out by hand you can get the answer.
 

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