一道英语的数学题 看不懂啊the first term of a geometric series is 24 and the common ratio is 5/2.How many consecutive terms must be taken to give a sum of 609?
问题描述:
一道英语的数学题 看不懂啊
the first term of a geometric series is 24 and the common ratio is 5/2.How many consecutive terms must be taken to give a sum of 609?
答
0没有悬赏分,飘过
答
翻译的意思是:第一学期的几何级数是24和常见的比率是整合。多少次连续条件,必须采取给一笔609吗?
答
应该是4吧.首项为24,公比为5/2的这么个级数,多少项的和是609?
24*((5/2)^n-1)/(5/2-1)=609,解得n=4