已知(An)為等差數(shù)列，d不等于0，a1,a3,a9成等比數(shù)列，求(a1 a3 a9)/(a2 a4 a10)的值。已知(An)為等差數(shù)列，d不等于0，a1,a3,a9成等比數(shù)列，求(a1+a3+a9)/(a2+a4+a10)的值。

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已知(An)為等差數(shù)列，d不等于0，a1,a3,a9成等比數(shù)列，求(a1+a3+a9)/(a2+a4+a10)的值。設(shè)公差為d , 則a3 =a1 +2d ,a9 = a1 + 8d所以 ( a1 +2d )^2 =a1 * (a1 + 8d)解得：d = a1 所以原式 = (a1+a1+2d+a1+8d)/(a1+d+a1+3d+a1+9d) = 13/16