{0,2,4,6,8}:
问题描述:
{0,2,4,6,8}:
{3,9,27 ,81……};
{1/2,3/4,5/6,7/8 ……};
用描述法表示下列集合
答
{x|x=2n,n=0,1,2,3,4}
{x|x=3n,n=1,2,3,4...}
{x|x=n/(n+1),n=2k-1,k=1,2,3...}