∵a1,a3,a9 成等比数列∴a3²=a1×a9又因为﹛an﹜是等差数列∴(a1+2d)²=a1(a1+8d)∴4a1d=4d²∴d=0或a1=d(1)d=0时,an=a1∴(a1+a4+a2)/(a8+a5+a7)=3a1/3a1=1(2)a1=d,an=a1+(n-1)d=na1∴(a1+a4+a2)/(a8+a...