題目是這些:
1. 2分之1+4分之1+8分之1+16分之1+32分之1+64分之1+....= ? (無限+上去的和)
2. 3分之1+9分之1+27分之1+81分之1+243分之1+729分之1+....= ?(無限+上去的和)
3. 10分之1+100分之1+1000分之1+10000分之1+100000分之1+1000000分之1+....= ?(無限+上去的和)
求解他們的公式與算法舉例 贈20點!!
求解 等比級數 算法與公式
2014-01-07 9:49 pm
回答 (1)
2014-01-07 10:21 pm
✔ 最佳答案
無限項和 = S(∞) = a/(1-r)1. (1/2) + (1/4) + (1/8) + (1/16) + (1/32) + (1/64) + .................
a = (1/2)
r = (1/2)
S(∞) = a/(1-r) = (1/2)/[1-(1/2)] = 1
2.(1/3) + (1/9) + (1/27) + (1/81) + (1/243) + (1/729) + .................
a = (1/3)
r = (1/3)
S(∞) = a/(1-r) = (1/3)/[1-(1/3)] = 1/2
3.(1/10) + (1/100) + (1/1000) + (1/10000) + (1/100000) + (1/1000000) + .................
a = (1/10)
r = (1/10)
S(∞) = a/(1-r) = (1/10)/[1-(1/10)] = 1/9
收錄日期: 2021-04-27 20:35:15
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https://hk.answers.yahoo.com/question/index?qid=20140107000016KK02849