有关亚马孙平原的描述正确的是( )
A:河网稀疏
B:气候炎热干燥
C:地势东高西低
D:分布着茂密的热带雨林
(Ⅰ)求函数f(x)的解析式及其单调增区间;
(Ⅱ)若对任意x1,x2∈0, π2 ,都有|f(x1)﹣f(x2)|≤a,求实数a的取值范围.
Whose pen is it? It____ Peter's. His name is on the cover.