有條數唔識.急求

2008-11-14 3:33 am

hence calclate the sum of the first 10 term of sequence

4,-4^2,4^3,-4^4,........

唔該教我.詳細小小.

回答 (3)

2008-11-14 3:41 am

✔ 最佳答案

呢個係等比數列
首頂a=4 , 公比係R=-4 項數n=10

公式sum = a(R^n-1) / (R-1)

=-838860

👍 0 👎 0

2008-11-19 3:50 am

呢個係等比數列
首頂a=4 , 公比係R=-4 項數n=10

公式sum = a(R^n-1) / (R-1)

=-838860
the answer is wrong

>__

👍 0 👎 0

2008-11-14 4:05 am

有d唔明 1st term係4.第 2個term係-4^2 姐係16 佢係既r唔係4咩?點解係-4 既?

👍 0 👎 0