2021 National Question 4 Single-choice Differentiating 2021_全国甲卷 (2021·文) 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 →