a(n) = a2^(n-1),n = 1,2,...
2^30 = a(1)*a(2)*...*a(30) = a^30*2^[1 + 2 + ...+ 29] = a^30*2^[29*30/2],
a(3)*a(6)*...*a(90) = [a2^2]*[a2^5]*...*[a2^89] = a^30*2^[2 + 5 + ...+ 89)] = a^30*2^[(2+89)*30/2] = a^30*2^[29*30/2]*2^[62*30/2]
= 2^30*2^[31*30] = 2^[30*32] = 2^[960]
设由正数组成的等比数列,公比q=2,且a1*a2.*a30=2^30,则a3*a6*a9*.*a90等于多少
设由正数组成的等比数列,公比q=2,且a1*a2.*a30=2^30,则a3*a6*a9*.*a90等于多少
数学人气:229 ℃时间:2020-05-14 23:22:30
优质解答
我来回答
类似推荐
- 设由正数组成的等比数列,公比q=2,且a1a2…a30=230,则a3a6a9…a30等于( ) A.210 B.215 C.216 D.220
- 设由正数组成的等比数列,公比q=2,且a1a2…a30=230,则a3a6a9…a30等于( ) A.210 B.215 C.216 D.220
- 已知等比数列{an}中,公比q=2,且a1*a2*a3...a30=2^30,则a3*a6*a9...a30=
- 设(an)是由正数组成的等比数列,公比q=2,且a1*a2*a3*```*a30=2^30,那么a3*a6*a9*```*a18=?
- {an}是正数等比数列,公比q=2,若a1*a2*a3*…*a30=2^30,求a3*a6*a9…a30.