1和0.9的循环哪个大?

0.9的循环等于1：
0.9+0.09+0.009+0.0009+.
=0.9×(1+0.1+0.01+0.001+.) //:圆括号内为等比级数：首项为1,公比为：0.1；项数：∞；
=0.9 × lim(n->∞) a1(1-q^n)/(1-q)
=0.9 × lim(n->∞)(1-0.1^n)/(1-0.1) //:0.1^∞=0
=0.9/0.9
=1