設f(x)為三次多項式,若f(2)=f(4)=f(-1)=3,f(1)=-15,求f(x)? 求詳解過程做法?
回答 (1)
2015-10-26 2:44 pm
✔ 最佳答案
設f(x) = a(x-2)(x-4)(x+1) + 3則f(1) = a(1-2)(1-4)(1+1) + 3 = -15
6a + 3 = -15
a = - 3
f(x) = -3(x-2)(x-4)(x+1) + 3
= -3(x²-6x+8)(x+1) + 3
= -3(x³-6x²+8x+3x²-6x+8) + 3
= -3(x³-3x²+2x+8) + 3
= -3x³+9x²-6x-21
收錄日期: 2021-04-24 23:22:35
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20151026063512AARmyi4