Current location - Training Enrollment Network - Mathematics courses - Yancheng City, Jiangsu Province, 20 1 1 Detailed explanation of mathematical science test questions in the first semester of senior three 14.
Yancheng City, Jiangsu Province, 20 1 1 Detailed explanation of mathematical science test questions in the first semester of senior three 14.
When m= 1, a 1=3, a2=6, a3=3, a4=6, a5=3, A6 = 6, A7 = 3 and A8 = 6.
S4n+4=36
When m> 1, a1<; 3。 an+ 1 / an = 2
s4n+4 = a 1×( 1-q^n)/( 1-q)
=3/(2^m- 1)×(2^(4n+4)- 1)
I don't know if it's right, it's for reference only.