搜题请搜索小程序“爱下问搜题”
问题 填空题
若Sn=
1
2
+
2
3
+
1
22
+
2
32
+…+
1
2n
+
2
3n
，则
lim
n→∞
Sn=______．
答案

∵Sn=

1
2
+
2
3
+
1
22
+
2
32
+…+
1
2n
+
2
3n

=(

1
2
+
1
22
+…+
1
2n
)+…+2(
1
3
+
1
32
+••+
1
3n
) ))

=

1
2
[1-(
1
2
)n]
1-
1
2
+2•
1
3
[1-(
1
3
)n]
1-
1
3

=2-(

1
2
)n-(
1
3
)n

则

lim
n→∞
Sn=
lim
n→∞
(2-
1
2n
-
1
3n
)=2

故答案为：2

听力题

根据下列各句句意和空白之后的汉语提示词，在答题卡指定区域的横线上写出对应单词的正确、完整形式，每空只写一词。

小题1:He is very reliable. That is to say, you can completely ________(依靠）on him.

小题2:He seemed to take great _______(高兴) in buying a new smart phone.

小题3:You will be informed when the book becomes_________(可使用的；可获得的).

小题4:She is always_____________(乐观的) about everything in spite of in trouble.   

小题5:You must learn to______(控制) your temper.

小题6:The police confirmed that the murder victim had been _________(毒死). 

小题7:Frank made a good __________(印象)in the first interview. 

小题8:They are afraid that we care too much about ourselves and are ________(不愿意)to cooperate with others.

小题9:No one really knows exactly when the first people arrived in                 now.(call)

没有人知道确切在什么时候第一批移民者到达我们今天称之为美国的地方。

小题10:A reporter begins by contacting people _________________________ and then prepares questions. (interview)

记者要先和被采访人联系，然后准备好要采访的问题。
查看答案
多项选择题

高原地区全麻应注意的是

A．特别重视防止缺氧

B．避免血压剧烈波动

C．麻醉后必须继续进行吸氧治疗24～48h

D．完全清醒后再拔除气管导管

E．术后镇痛慎用麻醉性镇痛药
查看答案