【单选题】58 / 449距离相对误差近似公式为?AD/(3R)D/(3R)D/(3R)BD2/(3R2)D^{2}/(3R^{2})D2/(3R2)正确C3R2/D23R^{2}/D^{2}3R2/D2D2R/D2R/D2R/D参考答案B参考解析ΔD/D=D2/(3R2)\Delta D/D=D^{2}/(3R^{2})ΔD/D=D2/(3R2)。