已知列表lst=[1,2,3,4,5],则依次执行表达式lst.insert(0,-1),lst.pop(1)后,表达式sum(lst)的值为()
已知当t=1,2,3,4,5且y=1,2,…,10时,有
如果在y=5时投资1000元,持续3年,计算等价的均衡利率.
A)1,2,3,4,5
B)1,2,4,5,7
C)1,4,3,7,6
D)1,4,3,7,2
已知离散型随机变量X的概率分布列表如表5-15:
表5-15 | |||
X | -3 | 1 | 2 |
P | frac{2}{3} | frac{1}{6} | frac{1}{6} |
则数学期望E(X)=______.
已知载波输出信号为uc(t)=Umcos(ωct),调制信号uΩ(t)=UΩmcos(Ωt),调制灵敏度为k,试列表写出普通调幅波、调频波和调相波的振幅、瞬时角频率、瞬时相位和输出电压表示式,并画出它们相应的波形。
The word "regression" in the lst paragraph is best replaced by
[ A] backward movement.
[ B] uncontrolled inclination.
[ C] rapid advancement.
[ D] unexpected restoration.
The relation between the two paragraphs is that in the 2nd paragraph the author
[A] challenges the viewpoint in the lst paragraph.
[B] modifies his view expressed in the lst paragraph.
[C] provides the reason for the argument in the lst paragraph.
[D] further analyzes the issue discussed in the lst paragraph.
已知在管式反应器中进行液相反应:
A→R+S
其为吸热反应,反应管外油浴温度(Tc)恒定为613K,假定已知其管内温度(T)与反应物的转化率(xA)的关系为
K
式中,速率常数,其中,A=1.17×1017min-1,Ea=1.84×105J·mol-1,气体常数R=8.314J·mol-1·K-1,T为管内反应温度。
若反应器入口温度为613K,反应器出口转化率为90%,试列表计算转化率每变化0.1,管式反应器内相应的温度。
What does "round the clock" mean (lst sentence in paragraph 3)?
A.The diners serve customers half a day.
B.The diners serve customers at certain hours.
C.The diners serve customers 24 hours a day.
D.The diners serve customers only on weekdays.
A.溴甲酚紫葡萄糖肉汤
B.LST肉汤
C.煌绿乳糖胆盐肉汤(BGLB)
D.月桂基硫酸盐胰蛋白胨