已知数列{an}中,a1=-1,且(n+1)an,(n+2)an+1,n成等差数

题型:解答题

问题:

已知数列{an}中,a1=-1,且 (n+1)an,(n+2)an+1,n 成等差数列.

(Ⅰ)设bn=(n+1)an-n+2,求证:数列{bn}是等比数列;

(Ⅱ)求{an}的通项公式;

(Ⅲ)(仅理科做) 若an-bn≤kn对一切n∈N*恒成立,求实数k的取值范围.

考点:等比数列的定义及性质
题型:解答题

阅读下列材料(16分)

材料一 在1850年以后,英国同俄国的冲突大概是不可避免的了。全欧洲各个国家革命运动失败后,俄国在欧洲大陆上几乎没有劲敌了。而这次欧洲大陆各国的革命运动之所以失败主要是由于俄国干涉的结果。……俄国则是欧洲反动势力的强大堡垒、后备阵地和后备军。

——《人民的英国史》

材料二 为了加快和约条款的签订,并防止(甚至在将来)从朕方面产生任何贪功和侵略的思想,朕同意规定一些特别的预防办法,以免朕的军舰和土耳其的军舰在黑海发生冲突。同意在比萨拉比亚南部,邻近多瑙河的地方划定新的国界线。

——沙皇亚历山大二世“关于结束克里米亚战争的宣言”(1856•3)

材料三 在克里米亚战争中,英国和法国的动机完全是自私的,但是如果俄国在这次战争中取得胜利,则将成为全欧洲民主和进步进步的灾难。

材料四 这次战争之所以取得胜利,是因为俄国的 * * 和官吏们更加无能。俄国的严重弱点,过去为外界所没想像到的,现在都暴露出来了。

——《人民的英国史》

回答:

①材料一认为1850年后英俄冲突不可避免的原因是什么?你是否赞同?为什么?

②据材料二,指出克里米亚战争的结局,并结合所学知识分析其影响。

③据材料四并结合所学知识,分析俄国战败的深层原因

题型:解答题

图1-11中绘出3类材料——金属、离子晶体和高分子材料之能量与距离的关系曲线,试指出它们各代表何种材料。

题型:解答题

阅读理解。

     We all long for friendship, but how to make a friend?"The best time to make a friend is before you need

one." Joy Steven said. The following are some tips for you.

     People equal friends

     Friends usually begin with strangers. Getting in touch with other people is the first step to make a friend.

Friends can't be made in empty air. Best friends take time to make.

     Friends understand friends 

     Friends understand each other when talking. Many unpleasant personal quarrels can be avoided if you will

take the time to understand others' feelings and points of view.

     Friends touch friends

     Touching is a warm from of communication between friends. When you see best friends communicating,

you will notice them stand close together, touch each other comfortably and listen to each other. Sometimes

a friendly touch is more powerful than words.

     Friends praise friends

     Praise is a powerful tool to make a friend. Honest praise can affect (影响) your friends' lives. So try to

praise your friends, including your general ones.

     Friends can loyal (忠诚的) and trustworthy

     Trust and loyalty go hand in hand for friends. Friends can share secrets with you, because good friends

never break confidence (信心) and are loyal forever.

1. From Joy Steven's words, we can conclude that _____. [ ]

A. a friend in need is a friend indeed

B. it is never too late to make a friend

C. it is late to make a friend when you need one

D. everyone needs a friend in his life

2. To make and keep many friends, you need to do the following EXCEPT _____. [ ]

A. get in touch with people

B. understand your friends

C. praise your friends

D. quarrel with your friends

3. The passage mainly tells us _____. [ ]

A. how to communicate with a friend

B. how to develop friendship

C. when to make a friend

D. how to praise a friend

题型:解答题

含甾体生物碱

题型:解答题

声音是描述故障的间接特征参量,在实际测量中可用( ,)加以描述。

A.噪声

B.超声

C.速度

D.加速度

E.声发射

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