已知函数f(x)=x2-2(n+1)x+n2+5n-7, (Ⅰ)设函数y=f(x

题型:解答题

问题:

已知函数f(x)=x2-2(n+1)x+n2+5n-7,

(Ⅰ)设函数y=f(x)的图像的顶点的纵坐标构成数列{an},求证:{an}为等差数列;

(Ⅱ)设函数y=f(x)的图像的顶点到x轴的距离构成数列{bn},求{bn}的前n项和Sn

考点:等差数列的定义及性质数列求和的其他方法(倒序相加,错位相减,裂项相加等)
题型:解答题

影响能力的因素很多,其中( )是以已有的知识经验为中心,对客观现实的概括和间接的反应。

A.感觉、知觉和观察力

B.注意

C.思维

D.记忆

题型:解答题

Questions from 36 to 40 are based on the following passage: Negotiations work wonders. This is particularly so in international business since it is mostly through negotiations that exporters and importers bridge their differences and reach a fair and mutually satisfactory deal. By presenting a more comprehensive negotiating package in a well planned and organized manner, exporters should be able to improve the effectiveness of their business discussions and in the long term the profitability of their export operations. To avoid being confronted by costly demands, an exporter should try to determine the buyer’s real interest in the products from the outset. This can be ascertained through appropriate questions but must also be based on research and other preparations before the negotiations. Only then can a suitable counter-proposal be presented. To achieve a favorable outcome from the negotiations, an exporter should draw up a plan of action beforehand, which addresses a few key issues. Experienced negotiators consider that as much as 80% of their overall time devoted to negotiations should go to such preparations. The preliminary work should be aimed at obtaining relevant information on the target market and the buyers of the products. It should also include developing counter-proposals if objections are raised on any of the exporter’s opening negotiating points. The preparations should thus involve formulating the negotiating strategy and tactics.In international marketing negotiations, it is advisable for small and medium-sized exporters not just to limit their discussions to pricing issues, although pricing is a key factor in any business transaction, exporters should give more attention to the full range of marketing factors. They should stress the strengths of their firms and products and match them with the perceived needs of the buyers. Once these issues have been covered, they can consider the question of price and are able to develop a profitable business.

A successful negotiator should be().

A.aggressive 

B.mild

C.well-prepared

D.hesitative

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下列哪项是溶组织阿米巴原虫的致病形态()

A.幼虫

B.大滋养体

C.小滋养体

D.包囊

E.虫卵

题型:解答题

鉴别皮质激素类药物主要依据的分子结构特征为

A.C17-α-醇酮基

B.C3-酮基

C.酚羟基

D.活泼次甲基

E.炔基

题型:解答题

盛放石灰水(Ca(OH)2)的试剂瓶放置时间久了,在瓶内壁上会形成一层白色物质,你认为该白色物质是______(填化学式),该现象说明空气中含有______(填化学式).如果要除去该白色物质,可以选用的试剂是______(填名称),反应的文字表达式是______.

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