hi, Just do as u have thought. The known information,b/n-1< b < |aij| is just used to ensure that the matrix A is non-singular that it is a invertable matrix, that is A-1 exists.

不好意思还是确定不了它不为0……能不能说得详细一点？按照我的思路要从每一级低阶推出行列式不为0实在太笨了……|||||||||||||||

对n阶行列式进行n-1次初等行变换(或初等列变换),然后将其它化为上三角行弄式(或下三角行列式),

最后比较对角线上元素的大小并计算出行列式即可.