设等差数列{an}的公差d≠0,数列{bn}为等比数列,若a1=b1,b2=a3 b3=a2,则bn的公比为

问题描述:

设等差数列{an}的公差d≠0,数列{bn}为等比数列,若a1=b1,b2=a3 b3=a2,则bn的公比为