已选分类
理学数学
单选题设函数，则______。A.x=3及x=e都是f(x)的第一类间断点B.x=3及x=e都是f(x)的第二类间断点C.x=3是f(x)的第一类间断点，x=e是f(x)的第二类间断点D.x=3是f(x)的第二类间断点，x=e是f(x)的第一类间断点
单选题i，k均为正整数(positive integer)，问i和k的最大公约数(greatest common divisor)是多少? (1)j=k+1 (2)jk is divisible by 5 (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ThefigureaboveisaregularhexagonwithcenterH,Theshadedareaisaparallelogramthatsharesthreeverticeswiththehexagon;itsfourthvertexisthecenterofthehexagon.Ifthelengthofonesideofthehexagonis8centimeters,whatistheareaoftheunshadedregion?
单选题A painter has painted one-third of a rectangular wall which is ten feet high. When she has painted another 75 square feet of wall, she will be three-quarters finished with the job. What is the length (the horizontal dimension) of the wall? (A) 18 feet (B) 12 feet (C) 10 feet (D) 9 feet (E) 6 feet
单选题
单选题公差不为零的等差数列的第二、第三和第七项恰好构成等比数列，则它的公比是______．
单选题设A为3阶矩阵，A*为A的伴随矩阵，A的行列式|A|=2，则|-2A*|=______。
A.-25
B.-23
C.23
D.25
单选题Two cars left the same town traveling in the same direction. Car A traveled 40 miles per hour and left at 3:20. Car B traveled 50 miles per hour and left at 4:40. At what time will car B catch up with car A? (A) 10:00 (B) 9:00 (C) 8:40 (D) 7:20 (E) 6:10
单选题
单选题在价格为100元时，商品的需求弹性为-0.5，则价格下跌到99元时，需求量将______． A．下降50% B．上升50% C．下降0.5% D．上升0.5%
单选题3, k, 2, 8, m, 3 The arithmetic mean of the list of numbers above is 4. If k and m are integers and k≠m, what is the median of the list?
单选题函数的值域是______.A．-1＜y≤1B．-1≤y＜1C．-1≤y≤1D．0≤y≤1
单选题If n is a positive integer and n2 is divisible by 72, then the largest positive integer that must divide n is (A) 6 (B) 12 (C) 24 (D) 36 (E) 48
单选题X是否满足0＜X＜1?(1)(2)(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．
单选题已知21g(x-2y)=lgx+1gy，则．A．1B．2C．1或2D．4E．1或4
单选题某人用35万元资金投资股票市场，第一季度账面资金增加了15%，第二季度结账时，账面资金比最初投入资金增加5万元，则在第二季度资金与第一季度相比______． A．增加0.621% B．增加0.957% C．减少0.621% D．减少0.957%
单选题Ifthespacesbetweentheletteredpointsinthefigureaboveareallequal,thenisequaltowhichofthefollowing?
单选题设f(x)存在二阶连续导数，且满足xf″(x)+3x[f′(x)]2=1-e-x，又x0为驻点，则______． A．f(x0)为f(x)的极大值 B．f(x0)为f(x)的极小值 C．(x0，f(x0))为f(x)的拐点 D．f(x0)非极值，(x0，f(x0))也非拐点
单选题The contents of a certain box consist of 14 apples and 23 oranges. How many oranges must be removed from the box so that 70 percent of the pieces of fruit in the box will be apples? (A) 3 (B) 6 (C) 14 (D) 17 (E) 2O
单选题