In 2013, the human population reached 7.1 billion with an annual growth rate of 1.1%. How many people will there be in 2014? A: 7.8 x 106 B: 7.8 x 107 C: 7.8 x 108 D: 7.1 x 106 E: 7.1 x 107

lim[√(x²+x)-√（x²-x)],x→∞

与二进制数1100101等值的十进制数是 A: 101 B: 106 C: 87 D: 93

设f（x）=3x，g（x）=x2，则函数g[f（x）]-f[g（x）]=（）。

[lncos(x-1)]/[1-sin(πx/2)]x≠1

怎么证明D(X)=E(X^2)-[E(X)]^2和D(X)=E[X-E(X)]^2

设f(x)=1/1-x求f[f(x)]和f{f[f(x)]}

已知列表lst=[ [‘苹果’,’红色’] , [‘葡萄’,’紫色’] , [‘草莓’,’红色’] ]，则以下能够获取所有水果名称列表的表达式是： A: [ x[0] for x in lst ] B: [ x[1] for x in lst ] C: [ x(0) for x in lst ] D: [ x for x in lst if x==’水果’]

阅读下列程序,程序输出的结果是______。bb=100 def func1(x,y): bb=x+y return bbdef func2(x,y): global bb bb=x+y return bbs1=func1(2,4)s2=func2(2,4)print(s1,s2,bb) A: 6 100 106 B: 6 106 106 C: 6 6 100 D: 6 6 6

已知随机变量X的数学期望E(X)存在，则下列等式中不一定成立的是 未知类型：{'options': ['E[E(X)] = E(X)', '', 'E[X−E(X)] = 0', 'E[X+E(X)] = 2E(X )'], 'type': 102}