设在点的某邻域内连续,函数可导,且,则A.兀f(0,0)B.兀/2f(0,0)C.1/2f(0,0)D.f(0,0) 设在点的某邻域内连续,函数可导,且,则A、兀f(0,0)B、兀/2f(0,0)C、1/2f(0,0)D、f(0,0) 发布时间:2025-08-19 09:22:32