maths
2007-11-20 3:26 am
Let r1,r2,r3,....rn be a geometric sequence.Show that r1^3,r2^3,r3^3,....rn^3 is also a geometric sequence.
回答 (1)
2007-11-20 3:46 am
✔ 最佳答案
Since r1,r2,r3,....rn is a geometric sequencei.e.( rn/rn-1)=...=(r3/r2)=(r2/r1) ---( *)
Now , Consder
(r3)^3/(r2)^3=(r3/r2)^3
=(r2/r1)^3 By (*)
=(r2)^3/(r1)^3
In general (rn)^3/(rn-1)^3=...=(r3)^3/(r2)^3=(r2)^3/(r1)^3
i.e. r1^3,r2^3,r3^3,....rn^3 is also a geometric sequence.
收錄日期: 2021-04-13 21:57:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071119000051KK02940