【单选题】er: d 5. Mike consumes two commodities, x and y , and his utility function is min{ x + 2 y , y + 2 x }. He chooses to buy 8 units of good x and 16 units of good y . The price of good y is $.50. What i...
【简答题】A.Moveable metal type began to be used in printing. B.Chinese printing technology was first introduced. C.The earliest known book was published. D.Metal type was imported from Korea.
【单选题】造成人类遗传病的原因有多种。在不考虑基因突变的情况下,下列说法正确的是
A.
21三体综合征一般是由于第21号染色体结构异常造成的
B.
猫叫综合征是第5号同源染色体中缺失1条造成的遗传病
C.
冠心病属于多基因遗传病,这类遗传病在群体中发病率较高
D.
若父母表现型均正常,生一个患红绿色盲男孩的概率为1/4
【多选题】在线电压UL =220V,频率 f =50Hz的三相电源上,接一个对称三角形联结的感性负载,已知每相阻抗Zp =8 Ω,则以下参数正确的是()
【简答题】function y=two_min(x) if x<20 y=-exp(-(x/20).^2); else y=-exp(-1)+(x-20)*(x-22); end
【单选题】The young inventor wants to take out a ________ on his new type of printing machine.
【简答题】What are the advantages of movable type printing?
【单选题】Which type of printing is more convenient based on the passage()
【简答题】invented the art of printing(movable type printing) in the Northern Song Dynasty.
【简答题】三相对称感性负载三角形( D )联结,三相对称电源的线电压为 220V ,测得电路的线电流为 38A ,负载的有功功率为 11.583kW 。试求: 1 电路的功率因数; 2 确定负载的电阻值; 3 确定负载的电抗值。