(10分)设D=(x,y)|x2+y2≤4且(x-1)2+y2≥1,y≥0),计算
参考答案:
解析:[注] 计算[*]用到华里士公式,请考生切记此公式.
完成下列反意疑问句.
1. He isn't a student, __________?
2. He likes basketball, __________?
3. They'll go to Shiqi tomorrow, __________?
4. Your mother can't swim , __________?
5. Tom has had his supper, __________?
液氧泵向换热器输送氧之前,须先对换热器氧气管线进行()
A.预冷
B.充压
C.吹扫
D.清洗