题目内容
设二重积分$I=\int_1^2 d x \int_{\ln x}^{x-1} f(x, y) d y+\int_2^e d x \int_{\ln x}^1 f(x, y) d y$交换积分次序后，$I$ 等于
$\text{A.}$ $\int_0^1 d y \int_{e^y}^{y+1} f(x, y) d x$
$\text{B.}$ $\int_0^1 d y \int_{y+1}^{e^y} f(x, y) d x$
$\text{C.}$ $\int_0^{\ln 2} d y \int_{y+1}^{e^y} f(x, y) d x+\int_{\ln 2}^1 d y \int_{y+1}^e f(x, y) d x$
$\text{D.}$ $\int_0^1 d y \int_{e^y}^2 f(x, y) d x+\int_0^1 d y \int_2^{y+1} f(x, y) d x$