0.38(0.22)kv与0.38(0.22)kv架空线路交跨且在最大弛度时,导线间最小垂直距离为()m。
A.1.0
B.1.5
C.2.0
D.2.5
A.1.0
B.1.5
C.2.0
D.2.5
1 一台三相同步发电机,星形联结。SN=70 000 kV.A,UN=13.8 kV,λN=0.85(电感性),IfN=100 A。Xd=2.72 Ω,XΩ=1.90 Ω,R1忽略不计。设磁路不饱和,If与E0成正比。试求当I1=2 000 A,λ不变,而要保持电压仍等于额定电压时,If应调节到多少?
已知某商品的生产成本C=C(x)为产量x的函数,C与x有如下关系:
又知产量为零时的固定成本C(0)=C0≥0.求成本函数C(x).
A.1.158
B.1.218
C.1.196
D.1.184
2007年,美国人消费了192亿包香烟。他们支付的平均零售价格为4.5美元/包。
(1)给定供给弹性为0.5,需求弹性为-0.4,推导香烟的线性需求与供给曲线。
(2)香烟税是联邦税种,2007年大约为每包40美分,该税收对市场出清价格和产量产生了什么影响?
(3)消费者将支付多少香烟税?生产者呢?
In 2007,Americans smoked 19. 2 billion packs of cigarettes. They paid an average retail price of $ 4.50 per pack.
a. Given that the elasticity of supply is 0. 5 and the elasticity of demand is -0. 4 , derive linear demand and supply curves for cigarettes.
b. Cigarettes are subject to a federal tax, which was about 40 cents per pack in 2007. What does this tax do to the market - clearing price and quantity?
c. How much of the federal tax will consumers pay? What part will producers pay?