一个数乘小数,积一定比这个数小
路的一边是田野,葱葱绿绿的,非常可爱,像一片柔软的绿毯。
请根据对话选词填空
ducks quiet nature park people buildings
There is a____. The nature park is____. There aren't many ____. There aren't many tall____. There are some animals. They are____and rabbits.
设双曲线x24﹣y2=1的右焦点为F,点P1、P2、…、Pn是其右上方一段(2≤x≤25,y≥0)上的点,线段|PkF|的长度为ak,(k=1,2,3,…,n).若数列{an}成等差数列且公差d∈(15,55),则n最大取值为____