冰罗兰
幼苗
共回答了25个问题采纳率：96% 举报
解: 设 f(x) = ax^3+bx^2+cx+d
则 f(-1) = -a+b-c+d = 0
f(1) = a+b+c+d = 0
f(2) = 8a+4b+2c+d = 3
f(3) = 27a+9b+3c+d = 16
增广矩阵 =
-1 1 -1 1 0
1 1 1 1 0
8 4 2 1 3
27 9 3 1 16
-->
1 0 0 0 1
0 1 0 0 -1
0 0 1 0 -1
0 0 0 1 1
所以 a=1,b=-1,c=-1,d=1
即有 f(x) = x^3-x^2-x+1.
1年前
6
