Question

看到了几题有趣的英语数学题 哪位数学好的英语大虾帮忙解释，并说一下做题思路 谢了

For each positive integer n ,the mean of the first n terms of a sequence is n . What is the 2008th term of the sequence ? 答案是4015 这个题目什么意思？

Vertex E of equilateral 三角形ABE is in the interior of unit square ABCD .Let R be the region consisting of all points inside ABCD and outside 三角形ABE whose distance from AD is between 1/3 and 2/3 . What is the area of R ? 这道题目怎么理解？

Let a,b,c,d and e be five consecutive terms in an arithmetic sequence , and suppose that a+b+c+d+e=30 .Which of the following can be found ? 答案是 c 这道题怎么理解

Answer 1

1.为每一个正整数氮、平均的第n条件的序列n。什么是2008年期限的顺序的吗?
2.顶点E ABE等边的内部ABCD,让R是单位广场该地区所有点组成的内部和外部安倍的距离ABCD是在公元1 / 3和2 / 3。什么是面积R呢?
3.让a、b、c、d、e是5个连续的条件在一个算术序列,并假设一个+ b + c + d + e = 30他以下可以找到?