设成等差数列的三个数为a-d,a,a+d,(d>0),有(a-d)+a+(a+d)=3a=12a=4根据最小数加上1,则三数成等比数列有(4-d+1)/4 = 4/(4+d)解得d = (1-sqrt(17))/2 (舍去）或d = (1+sqrt(17))/2原来三个数为(7-sqrt(17))/2,4,(9+sqr...