Re: [中學] 請問一題多項式
※ 引述《jenshi (小旭)》之銘言：
: https://imgur.com/a/Cwsff
: x代-1、3好像也都不大好算@@"
f(x) = (x + 1)(x - 3)(x^3 + 7) + r(x)
= (x^2 - 2x - 3)(x^3 + 7) + (ax + b)
= (x^5 - 2x^4 - 3x^3 + 7x^2 - 14x - 21) + (ax + b)
= (ax + b)[x^4 - 4x^3 + 5x^2 - 3x - 7] + k
r(x) = ax + b
h(x) = k
=> a = 1
-4 + b = -2
=> b = 2
-21 + 2 = -14 + k
=> k = -5
r(x) + h(x) = x + 2 - 5 = x - 3
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 111.249.173.192
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1505933545.A.385.html
推
09/21 08:55, , 1F
09/21 08:55, 1F
→
09/21 08:58, , 2F
09/21 08:58, 2F
→
09/21 08:58, , 3F
09/21 08:58, 3F
討論串 (同標題文章)