a(n+1)-1=2(an-1)由a1-1=2得an-1=2*2^(n-1)=2^nan=2^n+1因为1/an无穷小且大于零故只要logm(x+1)小于或等于零即m(x+1)小于等于1x+1小于等于1/m即x小于等于1/m-1