合并这两句,就是你想用导数的定义求这个函数吧~导数定义f'(x) = lim(h->0) [f(x + h) - f(x)]/hf'(a) = lim(x->a) [f(x) - f(a)]/(x - a),就是函数在x = a处的导数,也即曲线在该点的斜率.y = 1/(1 + x)y' = lim(h->0...