单选题设随机变量X的概率密度为f(x)，a≠0是一常数，则可以作为某随机变量的概率密度的是

单选题{{B}}Directions:{{/B}}{{I}} Read the following passage. For each numbered blank there are four choices marked A, B, C and D. Choose the best one and mark your answers on ANSWER SHEET 1.{{/I}} The government is to ban payments to witnesses by newspapers seeking to buy up people involved in prominent cases{{U}} {{U}} 1 {{/U}} {{/U}}the trial of Rosemary West. In a significant{{U}} {{U}} 2 {{/U}} {{/U}}of legal controls over the press, Lord Irvine, the Lord Chancellor, will introduce a{{U}} {{U}} 3 {{/U}} {{/U}}bill that will propose making payments to witnesses{{U}} {{U}} 4 {{/U}} {{/U}}and will strictly control the amount of{{U}} {{U}} 5 {{/U}} {{/U}}that can be given to a case{{U}} {{U}} 6 {{/U}} {{/U}}a trial begins In a letter to Gerald Kaufman, chairman of the House of Commons media select committee. Lord Irvine said he{{U}} {{U}} 7 {{/U}} {{/U}}with a committee report this year which said that self regulation did not{{U}} {{U}} 8 {{/U}} {{/U}}sufficient control. {{U}} {{U}} 9 {{/U}} {{/U}}of the letter came two days after Lord Irvine caused a{{U}} {{U}} 10 {{/U}} {{/U}}of media protest when he said the{{U}} {{U}} 11 {{/U}} {{/U}}of privacy controls contained in European legislation would be left to judges{{U}} {{U}} 12 {{/U}} {{/U}}to Parliament. The Lord Chancellor said introduction of the Human Rights Bill, which{{U}} {{U}} 13 {{/U}} {{/U}}the European Convention on Human Rights legally{{U}} {{U}} 14 {{/U}} {{/U}}in Britain, laid down that everybody was{{U}} {{U}} 15 {{/U}} {{/U}}to privacy and that public figures could go to court to protect themselves and their families.

单选题曲线在处的法线方程为______A．B．y=1C．y=x+1D．y=x-1

单选题函数y=x2-x+1在区间[-1，3]上满足拉格朗日中值定理的ξ等于____．A．B．0C．D．1

单选题若三次多项式f(x)满足f(2)=f(-1)=f(1)=0，f(0)=4，则f(-2)=______．

单选题若函数F(x)和G(x)都是函数f(x)的原函数，则下列四个式子，正确的是( )。

单选题某交通岗共有3人，从周一到周日的七天中，每天安排一人值班，每人至少值2天，其不同的排法共有______

单选题设矩阵的秩为2，则______。A.a=0，b=0B.a=0，b≠0C.a≠0，b=0D.a≠0，b≠0

单选题设函数f(x)与g(x)在(a，b)上可导，考虑下列叙述： (1)若f(x)＞g(x)，则f′(x)＞g′(x) (2)若f′(x)＞g′(x)则f(x)＞g(x) 则

单选题设P(x)在(-∞，+∞)连续，且以T为周期，则是方程有解y=y(x)≠0且以T为周期的(A)必要非充分条件．(B)充分非必要条件．(C)充分且必要条件．(D)既不充分也不必要条件．

单选题设(1+x)+(1+x)2+(1+x)3+…+(1+x)20=a0+a1x+a2x2+…+a20x20，则a1+a2=( )。 (A) 210 (B) 231 (C) 1150 (D) 1540

单选题四个各不相等的整数a，b，c，d，它们的积a·b·c·d=9，那么a+b+c+d的值是______．A．0B．1C．2D．E．

单选题甲火车长92m，乙火车长84m，若相向而行，相遇后经过1.5s两车错过，若同向而行相遇后经6s两车错过。 (1)甲火车的速度为46m/s (2)乙火车的速度为42m/s

单选题设xlny=ylnx确定函数y=y(x)，则______．A．-1B．-1+eC．1D．1+e