典型例題十六(已修改)
2024-10-21 07:47 本頁面
【正文】 第一篇：典型例題十六典型例題十六例16 已知x是不等于1的正數(shù)，n是正整數(shù)，求證(1+xn)(1+x)n2n+1xn． 分析：從求證的不等式看，左邊是兩項(xiàng)式的積，且各項(xiàng)均為正，右邊有2的因子，因此可考慮使用均值不等式．證明：∵x是不等于1的正數(shù)，∴1+x2x0，∴(1+x)n2nxn．① 又1+xn2xn0．②將式①，②兩邊分別相乘得(1+xn)(1+x)n2xn2nxn，∴(1+xn)(1+x)n2n+1xn．說明：本題看起來很復(fù)雜，但根據(jù)題中特點(diǎn)，選擇綜合法求證非常順利．由特點(diǎn)選方法是解題的關(guān)鍵，這里因?yàn)閤185。1，所以等號(hào)不成立，又因?yàn)棰?，②兩個(gè)不等式兩邊均為正，所以可利用不等式的同向乘性證得結(jié)果．這也是今后解題中要注意的問題．第二篇：典型例題【典型例題】She had a great ___ for the town where she grew 【試題詳解】答案 A 她熱愛她長大的那座小鎮(zhèn) have an affection for 對(duì)??有感情affectation infection ，感染 affectionate 【常用短語】have an affection for sbsth 【詞匯補(bǔ)充】affect affectionate 【典型例題】How to talk to Martin is rather an____ 【試題詳解】答案 D 如何讓與火星人交談是一個(gè)學(xué)術(shù)性很強(qiáng)的問題。academic question 學(xué)術(shù)問題。advanced 高級(jí)的accurate 準(zhǔn)確的 absolute 絕對(duì)的【詞匯補(bǔ)充】academicals 博士服，碩士服 academic year 學(xué)年 academician 院士 academy 私立中學(xué) academicism 墨守成規(guī)【典型例題】When you __ big , believe big , and pray big , big things happen! 【試題詳解】答案是A。句意：當(dāng)你確認(rèn)偉大，相信你偉大，起到偉大，偉大的事情就會(huì)發(fā)生！affirm肯定，斷言；know知道；agree同意；ensure保證，確保?！镜湫涂碱}】The _____ of the past week had left her anxietiesB concernsC expectationsD anticipation 解析：由同意詞辨析可知此題答案選 A 意為過去一個(gè)星期的擔(dān)憂使她筋疲力盡。【典型考題】: Now,let us e to item on the 解析：答案是C。句意：現(xiàn)在讓我們討論議事日程上的第五項(xiàng)。agenda待議諸事一覽表；program（行動(dòng)）計(jì)劃；project工程，項(xiàng)目；plan計(jì)劃。【典型考題】Age affects the range of a person’s ______ A capacities B capabilitiesC capacious D capable 解析：答案選B 此題考查易錯(cuò)詞辨析。句意為年齡影響一個(gè)人能力的大小。Capacity 表示容量容積明顯不符合題意。后兩個(gè)答案分別為他們的形容詞形式?！镜湫涂碱}】He’s had no end of bad luck but he just seems to ______ every back to 解析：答案選A 句意：他總是遇到不如意的事，但是好像每次都能恢復(fù)過來。bounce back 指失意后恢復(fù)過來。【典型考題】Everyone is encouraged to ____ food and clothing for the attributeB contributeC stimulateD distribute 解析：答案為B ,此題考查對(duì)形近詞的區(qū)分。句意：鼓勵(lì)每個(gè)人為難民捐助食品和衣物。contribute 表示“捐贈(zèng)，出錢（力）”，因?yàn)楸绢}是鼓勵(lì)每個(gè)人，所以不可能是“分發(fā)”食品和衣物，只會(huì)是“捐贈(zèng)”【Derivative】contributor ，投稿者 ； contribution ，捐獻(xiàn)物contributive ，促成的 ；contributory ，捐助性的?！镜湫涂碱}】Everyone is encouraged to ____ food and clothing for the attributeB contributeC stimulateD distribute 解析：答案為B ,此題考查對(duì)形近詞的區(qū)分。句意：鼓勵(lì)每個(gè)人為難民捐助食品和衣物。contribute 表示“捐贈(zèng)，出錢（力）”，因?yàn)楸绢}是鼓勵(lì)每個(gè)人，所以不可能是“分發(fā)”食品和衣物，只會(huì)是“捐贈(zèng)”Counsel/kkkkkkk/ noun, verb n Noun 1.(formal)advice, especially given by older people or experts。a peiece of advice(尤指老年人或?qū)＜业?勸告，忠告，建議：Listen to the counsel of your a lawyer or group of lawyers representing sb in a court of law 律師：the counsel for the defence/ Verb 1 to listen to and give support or professional advice to sb who needs ：Therapists were brought in to counsel the to advise sb to do sth 建議，勸告（做某事）Most experts counsel caution in such cases.【Common phrases】a counsel of despair 知難而退的建議； a counsel of perfection 聽上去完美卻難以實(shí)行的建議； keep your own coun
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