【单选题】2 / 9设 a=(−y,x,0)a=(-y,x,0)a=(−y,x,0),则 rota\operatorname{rot}arota 等于A(0,0,2)正确B(0,0,-2)C(2,0,0)D(0,2,0)参考答案A参考解析(∂az/∂y−∂ay/∂z, ∂ax/∂z−∂az/∂x, ∂ay/∂x−∂ax/∂y)=(0,0,1−(−1))=(0,0,2)(\partial a_z/\partial y-\partial a_y/\partial z,\ \partial a_x/\partial z-\partial a_z/\partial x,\ \partial a_y/\partial x-\partial a_x/\partial y)=(0,0,1-(-1))=(0,0,2)(∂az/∂y−∂ay/∂z, ∂ax/∂z−∂az/∂x, ∂ay/∂x−∂ax/∂y)=(0,0,1−(−1))=(0,0,2)(K1−24K1-24K1−24)。