(x+1)^2+P(×+1)≡x^2+Q (要step)

2007-12-24 11:10 pm
(x+1)^2+P(×+1)≡x^2+Q (要step)
(x+1)^2+P(×+1)≡x^2+Q
求P及Q

左方
=(x+1)2+P(×+1)
=x2+2x+1+Px+1
-------------------↑ -------
上面點解“1”唔係“P”既?

回答 (2)

2007-12-24 11:31 pm
✔ 最佳答案
(x+1)^2+P(×+1)≡x^2+Q
x^2+2x+1+Px+P≡x^2+Q
x^2(P+2)x+P+1≡x^2+Q

比較係數
P+2=0
P=-2

Q=P+1=-2+1=-1

∴P=-2 , Q=-1
參考: me


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