Question

1求两个数分别是多少 2这两个数分别是这个数列的第几项

Answer 1

这个数列的通项是：An = -1*(-1/2)^n-1/512 = (-1/2)^9 = An * [1 + (-1/2)] = 1/2 * [-1 * (-1/2)^n] = (-1/2)^(n+1)n = 8,An=-1/256,An+1=1/512第 8 和第 9 项