按照目前世界平均开采强度，全球煤炭、石油和天然气分别可开采（）年。 A: 112、52、53 B: 113、53、55 C: 114、52、53 D: 115、53、55

复数A=3-4j,它的极坐标形式是(). A: 5∠-53 B: 5∠-37 C: 5∠53 D: 5∠37

已知复数3-j4，则其极坐标式为（）。 A: 5∠53° B: 5∠-53° C: 5∠127° D: 5∠-127°

‎已知复数3+j4，则其极坐标式为（）。‎ A: 5∠53° B: 5∠-53° C: 5∠127° D: 5∠-127°

a≠0，若53÷a<53，则a___1；若53÷a>53，则a___1．

根据乘方的意义可知：53=5×5×5，54=5×5×5×5，则53×54=（5×5×5）×（5×5×5×5）=57即53×54=57。想一想：

一个复数的代数式为3-j4,则它的极坐标式是()。 A: 5∠-37° B: 5∠53° C: -5∠37° D: 5∠-53°

下列程序段的执行结果是() int x=3： while(x＜=5) {printf("%d"，x-3)；x++；} A: 0 B: 112 C: 123 D: 12

复数A=3+j4，则复数A的模=，辐角=。（） A: 7 ， 37° B: 7 ， 53° C: 5 ， 37° D: 5 ， 53°

下列程序的运行结果是（ ）。t = 0 while t &lt; 5: print(t, " is less than 5") t = t + 1else: print(t, " is not less than 5") A: 0 is less than 51 is less than 52 is less than 53 is less than 54 is less than 55 is not less than 5 B: 1 is less than 52 is less than 53 is less than 54 is less than 55 is less than 55 is not less than 5 C: 0 is less than 51 is less than 52 is less than 53 is less than 54 is less than 5 D: 1 is less than 52 is less than 53 is less than 54 is less than 55 is less than 5