Originally posted by cxy1010 at 2011-02-13 09:27:46:
由题意得f（x）=x^2+x+2    x属于 R-【-1，2】 x^2-x-2
x属于 【-1，2].于是当x=1/2时，f（x）=-9/4,当x=2时，f（x）=0.
当x=-1时，f（x）=2.综上所述答案选D

Originally posted by cxy1010 at 2011-02-12 20:52:14:
[img]http://latex.codecogs.com/gif.latex?由题意得f（x）=gin{Bmatrix}&space;x^{2}+x+2&space;x\in&space;[-1,2]\\&space;x^{2}-x-2&space;x\in&space;R-[-1,2]\\& ...