Q: The n-th term Tn of a sequence T1,T2,T3,...is 7-3n.
a) Write down the first 4 terms of the sequence.
b) Find the sum of the first 100 terms of the sequence.
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中五Ｍａｔｈｓ（英文）
2008-02-25 2:17 am
回答 (1)
2008-02-25 2:27 am
✔ 最佳答案
a. first term=T(1)=7-3(1)=4second term=T(2)=7-3(2)=1
third term=T(3)=7-3(3)=-2
forth term=T(4)=7-3(4)=-5
b. 100th term=7-3(100)=-293
S(100)=100(4-293)/2
=-14450
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https://hk.answers.yahoo.com/question/index?qid=20080224000051KK03498