SAT I 每日一問:2012年11月21日
作者:滬江英語
來源:CollegeBoard
2012-11-21 09:51
The Correct answer is B.
Explanation
?
If?,?then?,?so the second condition fails. If?,then?,?so the second condition fails for this function also. The other three options satisfy?,?so it remains to check whether they satisfy the first condition.
If?,?and?,?then??and?,?so it is not true that??for all integers?. This means that the function??does not satisfy the first condition. If?,?and?,?then??and?,?so it is not true that??for all integers?. This means that the function??does not satisfy the first condition.
However, if?,?then?, for all integers?. Also,?.Therefore, the function??is the only option that satisfies both conditions.