2014 Beijing Question 2 Single-choice Differentiating 2014_北京卷 (2014·文) 2.(5 分)下列函数中,定义域是 R 且为增函数的是 A. $y=e^{-x}$B. $y=x$C. $y=\ln x$D. $y=|x|$ Answer keyB ☆ SaveCan't do it, show the explanation查看原卷 →