阅读短文，判断正误。

    I'm Fangfang. I live in a village. It's small but beautiful. Look! That is my house. There are some trees near it. Behind the house there's a big river. You can see boats on the river. Many ducks are beside the boats. How lovely! Oh, many flowers are among (在……之中）the trees. Let's get some for our teachers.

如图，一架长2.5米的梯子AB斜靠在竖直的墙AC上，这时B到墙AC的距离为0.7米．

（1）若梯子的顶端A沿墙AC下滑0.9米至A₁处，求点B向外移动的距离BB₁的长；
（2）若梯子从顶端A处沿墙AC下滑的距离是点B向外移动的距离的一半，试求梯子沿墙AC下滑的距离是多少米？

（Ⅰ）求f（x）的最小正周期；

（Ⅱ）求f（x）在 $-\frac{\pi }{12},\frac{\pi }{6}$ 上的最大值．