2011 National Question 2 Single-choice Differentiating 2011_大纲版 (2011·理) 2.(5分)函数 $y=2 \sqrt{x}(x \geq 0)$ 的反函数为( ) A. $y=\frac{x^{2}}{4} \quad(x \in R)$B. $y=\frac{x^{2}}{4} \quad(x \geq 0)$C. $y=4 x^{2} \quad(x \in R)$D. $y=4 x^{2} \quad(x \geq 0)$ Answer keyB ☆ SaveCan't do it, show the explanation查看原卷 →