化簡下列各式。
1.P和Q為常數。若 Qx+1/(x+4)(4x+5) ≡ 1/x+4 + P/4x+5，求P和Q的值。
答案：P= -1；Q= 3
Thanks......
F.4 Maths
2014-02-22 11:02 pm
回答 (3)
2014-02-23 8:41 am
✔ 最佳答案
(Qx+1)/(x+4)(4x+5) ≡ 1/(x+4) + P/(4x+5)Qx+1/(x+4)(4x+5) ≡ [(4x+5) + P(x+4)]/(x+4)(4x+5)
Qx+1 ≡ 4x+Px+4P+5
By comparing both side,
1 = 4P + 5
4P = - 4
P = - 1
Qx = 4x+Px
Q = 4+ (- 1)
= 3
2014-02-23 2:01 am
(Qx+1)/(x+4)(4x+5) ≡ 1/(x+4) + P/(4x+5)Qx + 1 ≡ (4x + 5) + P(x + 4)Qx + 1 ≡ (4 + P)x + (5 + 4P)比較同項系數，既Q = 4 + P 及 1 = 5 + 4P所以P = -1，Q = 3
2014-02-23 12:09 am
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