Maths
2011-10-05 6:49 am
1. Given an arithmetic series S(n)=T(1)+T(2)+T(3)+…+T(n)with T(n)=22-2n, find a) the first negative term of thesequence T(1),T(2),T(3),… ANS: -2b) the maximum value of S(n). ANS: 110How can I find the answer? Thanks!
回答 (1)
2011-10-05 7:17 am
✔ 最佳答案
a)22-2n=0n=11
therefore the first -ve term=T(12)=22-2(12)=-2
b)the last +ve term=T(10)=22-2(10)=2
the maximum value of S(n)=20+18+16+14+12+10+8+6+4+2=110
參考: me
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