求使函数y=2sin3x+1,x∈R取得最大值的自变量x的集合,并说出最大值是什么

2025-04-03 03:27:49
推荐回答(1个)
回答1:

(Ⅰ)∵{an}是首项为a1

1
4
,公比q=
1
4
的等比数列,
an(
1
4
)
n
bn+2=3log
1
4
an(n∈N*)
=3log
1
4
(
1
4
)
n
=3n,
∴bn=3n-2.
(Ⅱ)cn
3
bn?bn+1
=
3
(3n?2)(3n+1)
1
3n?2
?
1
3n+1

∴Tn=(1?
1
4
)+(
1
4
?
1
7
)+…+(
1
3n?2
?
1
3n+1
)

=1?
1
3n+1