函数y=2x的反函数是 ______．
∵y=2x，
∴x=log2y，
∴函数y=2x的反函数为y=log2x．
故答案为：y=log2x．
The most accurate way to account for flotation costs when issuing new equity to finance a project is to :（）
A. increase the cost of equity capital by dividing it by ( 1 - flotation cost).
B. adjust cash flows in the computation of the project NPV by the dollar amount of the flotation costs.
C. increase the cost of equity capital by multiplying it by ( 1 + flotation cost).
多房性液气胸的形成原因是（）。
A.感染
B.外伤
C.肺转移瘤
D.出血
E.胸膜粘连
