2. (5.0分) 设y=(arctan(x)/(2))^2，则dy=(4)/(4+x^2)arctan(x)/(2)dxA. 对B. 错

2. (5.0分) 设$y=(\arctan\frac{x}{2})^{2}$，则$dy=\frac{4}{4+x^{2}}\arctan\frac{x}{2}dx$

A. 对

B. 错