2021 National Question 4 Single-choice Differentiating 2021_全国甲 Paper 4. 下列函数中是增函数的为( ) A. $f ( x ) = - x$B. $f ( x ) = \left( { \frac { 2 } { 3 } } \right) ^ { x }$C. $f ( x ) = x ^ { 2 }$D. $f ( x ) = \sqrt [ 3 ] { x }$ Answer keyD ☆ SaveCan't do it, show the explanation查看原卷 →