题目设函数f(x)在 x=0 的某个邻域内有连续的二阶导-|||-数,且 '(0)=f''(0)=0, 则 __-|||-(A) x=0 必是f(x)的零点-|||-(B) x=0 必是f(x)的极值点-|||-(C)当 lim _(xarrow 0)dfrac (f''(x))(|x|)=1 时,(0,f(0))是拐点-|||-(D)当 lim _(xarrow 0)dfrac (f''(x))(sin x)=1 时,(0,f(0))是拐点题目解答答案