Insert 2 numbers between 5 and 17 so that the sequence formed is an arithmetic sequence.
Find the number of terms of the geometic sequence 2,6,18...,4374.
Find the number of terms of the geometic sequence 3.2,-1.6,0.8,...,-0.00625
Find the general term of the geometic sequence T(2)=1/9,T(5)=3
Find the general term of the geometic sequence T(2)=6,T(7)=192
Mathematics
2011-08-31 2:38 am
回答 (1)
2011-09-04 2:17 am
✔ 最佳答案
5=1*4+117=4*4+1
the 2 numbers=2*4+1 and 3*4+1=9 and 13
2=2*3^0
6=2*3^1
18=2*3^2
4374=2*3^7
number of terms=7-0+1=8
3.2=512/160=-(-2)^9/160
-1.6=-256/160=-(-2)^8/160
0.8=128/160=-(-2)^7/160
-0.00625=-1/160=-(-2)^0/160
number of terms=9-0+1=10
1/9=3^(2-4)
T(2)=3^(2-4)
3=3^(5-4)
T(5)=3^(5-4)
gernal term T(n)=3^(n-4)
6=6*2^(2-2)
T(2)=6*2^(2-2)
192=6*2^(7-2)
T(7)=6*2^(7-2)
general term T(n)=6*2^(n-2)
參考: me
收錄日期: 2021-04-13 18:12:22
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