已选分类
理学数学
单选题设在区间[a，b]上f(x)＞0，f'(x)＜0，f"(x)＞0，令，S2=f(b)(b-a)，S3=[f(a)+f(b)](b-a)，则______。A.S1＜S2＜S3B.S2＜S1＜S3C.S3＜S1＜S2D.S2＜S3＜S1
单选题Last year, a certain public transportation system sold an average (arithmetic mean) of 41,000 tickets per day on weekdays (Monday through Friday) and an average of 18,000 tickets per day on Saturday and Sunday. Which of the following is closest to the total number of tickets sold last year?
单选题x3＞y?(1)(2)x＞y(A)条件(1)充分，但条件(2)不充分．(B)条件(2)充分，但条件(1)不充分．(C)条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．(D)条件(1)充分，条件(2)也充分．(E)条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．
单选题某商店销售某种商品，该商品的进价为每件90元，若每件定价为100元，则一天内能销售出500件，在此基础上，定价每增加1元，一天便少售出10件，甲商店欲获得最大利润，则该商品的定价应为( )．
单选题How many two-digit numbers can be written using digits 0 through 6 if no digit can be repeated and 0 cannot be the first digit? (A) 49 (B) 42 (C) 36 (D) 30 (E) 25
单选题设函数f(x)可导，且f(0)≠0，则=______。A．B．C．D．
单选题函数f(x)和g(x)都在x=a处取得极大值，则函数F(x)=f(x)g(x)在x=a处______． A．必取极大值 B．必取极小值 C．不可能取极值 D．是否取极值不能确定
单选题设，则f(x)______。A.不存在间断点B.存在间断点x=1C.存在间断点x=0D.存在间断点x=-1
单选题求Median of a sequence (all the numbers are integers) (1)25%的数大于等于4 (2)35%的数小于等于2
单选题For integers a and b, if(a3-a2-b)1/2=7，what is the value of a? (1)a2-a=12 (2)b2-b=2
单选题设，则f[f′(x0)]=______．
单选题 District Number Of Votes Percent of Votes for Candidate P Percent of Votes for Candidate 1 800 60 40 2 1,000 50 50 3 1,500 50 50 4 1,800 40 60 S 1,200 30 70 The table above shows the results of a recent school board election in which the candidate with the higher total number of votes from the five districts was declared the winner. Which district had the greatest number of votes for the winner?
单选题将二阶矩阵A的第2列加到第1列得矩阵B，再交换B的第1行与第2行得单位矩阵，则A=______。A．B．C．D．
单选题Roncantypefiveformsofatestin4hours.Joancantypethesamefiveformsin6hours.Iftheyworktogether,howmanyhourswouldittakethemtotypetenformsofatest?
单选题
单选题
单选题设函数在(-∞，+∞)上连续，且，则常数a，b满足______。A.a＜0，b＜0B.a＞0，b＞0C.a≤0，b＞0D.a≥0，b＜0
单选题甲花费5万元购买了股票，随后他将这些股票转卖给乙，获利10%，不久乙又将这些股票返卖给甲，但乙损失了10%，最后甲按乙卖给他的价格的9折把这些股票卖掉了，不计交易费，甲在上述股票交易中______． A．不盈不亏 B．盈利50元 C．盈利100元 D．亏损50元
单选题某剧院正在上演一部新歌剧，前座票价为50元，中座票价为35元，后座票价为20元，如果购到任何一种票是等可能的，现任意购买到2张票，则其值不超过70元的概率为()．
单选题函数y=f(x)在点x=x0处取得极大值，则必有______． A．f′(x0)=0 B．f″(x0)＜0 C．f′(x0)=0且f″(x0)＜0 D．f′(x0)=0或不存在