题目内容
写出下面各数列的一个通项公式:
(1)-3,0,3,6,9,…;
(2),,,,,….
(1)a,b,a,b,a,b,…;
(2)8,-8,8,-8,8,-8,….
(1),,,,…;
(2)
(3)
(4)21,203,2005,20007,…;
(5)0.2,0.22,0.222,0.2222,…;
(6)1,0,1,0,…;
(7)
(1)3,5,7,9,…
(2),,,,,…
(3)-1,,-,,-,,…
(4),-1,,-,,-,…
(5)3,33,333,3333,…
(1)3,5,7,9,…;
(2),,,,,…;
(3)-1,,-,,-,,…;
(4),-1,,-,,-,…;
(5)3,33,333,3 333,….