21.函數(shù)f(x)=2
x和g(x)=x
3的圖象的示意圖如圖所示,設(shè)兩函數(shù)的圖象交于點(diǎn)A(x
1,y
1),B(x
2,y
2),且x
1<x
2.
(Ⅰ)請(qǐng)指出示意圖中曲線C
1,C
2分別對(duì)應(yīng)哪一個(gè)函數(shù)?
(Ⅱ)若x
1∈[a,a+1],x
2∈[b,b+1],且a,b∈{1,2,3,4,5,6,7,8,9,10,11,12},指出a,b的值,并說(shuō)明理由;
(Ⅲ)結(jié)合函數(shù)圖象的示意圖,判斷f(6),g(6),f(2007),g(2007)的大小,并按從小到大的順序排列.