下列()不应以卖出期货来避险。
A.生产原油者
B.农场
C.铜生产企业
D.大宗物资进口商
参考答案:D
Don’t kill your precious time chatting online all day long. It’s impossible for the lost time ,you know.
A.to make up
B.making up
C.to be made up
D.being made up
已知数列满足a1=1,an+1=2an+1(n∈N*)
(1)求证:数列{an+1}是等比数列;
(2)求{an}的通项公式.