[理工][線代]least square solution
請大大幫小弟看一下哪個步驟有誤?解不出正解~"~
Q:Find the least squares straight line that fits to the following four points:
(0,1),(1,3),(2,4),(3,4).
Sol:
X 0|1|2|3
Y 1|3|4|4
令y=ax+b
→ → -1 → →
已知ATAx=ATb<=>x = (ATA) ATb ATb
↓
┌ ┐ ┌ ┐ ┌ ┐ ┌ | ┐ ┌ | ┐
│1 0│ → ┌b┐ → │1│ │4 6│ │4 6|12│ │1 0| 3/2│
令A=│1 1│,x =│ │, b =│3│;ATA=│ │,解x:│ | │~│ | │
│1 2│ └a┘ │4│ │6 14│ │6 14|23│ │0 1| 1 │
│1 3│ │4│ └ ┘ └ | ┘ └ | ┘
└ ┘ └ ┘ 得b=3/2,a=1(錯..)
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◆ From: 180.177.80.211
※ 編輯: st900501 來自: 180.177.80.211 (01/20 18:35)
※ 編輯: st900501 來自: 180.177.80.211 (01/20 18:36)
推
01/20 18:45, , 1F
01/20 18:45, 1F
→
01/20 18:48, , 2F
01/20 18:48, 2F
推
01/20 18:54, , 3F
01/20 18:54, 3F
→
01/20 18:54, , 4F
01/20 18:54, 4F
→
01/20 18:59, , 5F
01/20 18:59, 5F
→
01/20 19:05, , 6F
01/20 19:05, 6F
推
01/20 20:44, , 7F
01/20 20:44, 7F
→
01/20 20:49, , 8F
01/20 20:49, 8F