Question

1.已知：2,-6,12,-20,30,-42.2.0,1,0,1,0,1.写出以上两个数列通项公式

Answer 1

1) 2,-6,12,-20,30,-42.an=(-1)^(n+1)*n(n+1)

2) 0,1,0,1,0,1.an=1/2+ (1/2)*(-1)^n