等比数列a+log23,a+log43,a+log163的公比是

显示全部楼层 · 2012-7-14 08:43:03

a+log23,a+log43,a+log163是等比数列，所以(a+log4(3))^2=( a+log2(3))( a+log16(3)) 2alog4(3)+ (log4(3))^2= (log2(3) +log16(3))a+ log2(3)* log16(3), 2alog4(3)+ (1/2*log2(3))^2= (log2(3) +1/4*log2(3))a+ log2(3)* [1/4*log2(3)], 2alog4(3)+ 1/4*(log2(3))^2= (5/4*log2(3))a+ 1/4*(log2(3))^2, 2alog4(3) = (5/4*log2(3))a 所以a...

千问 · 2012-7-14 08:43:03

没的公比的哦，a≠0，a+log23,a+1/2log23,a+1/4log23没的公比
a=0，公比为1/2...

千问 · 2012-7-14 08:43:03

等比数列a+log?3，a+log?3，a+log?16?3的公比是解：a+log?3；a+log?3=a+log?√3=a+(1/2)log?3；a+log?16?3=a+(1/4)log?3；三数成等比数列，故必有a...

千问 · 2012-7-14 08:43:03

公比是1/2设log23=b,则log43=1/2b,log163=1/4b因为是等比数列所以(a+1/2b)^2=(a+b)(a+1/4b)解得 ab=0又b≠0所以a=0所以公比=（1/2b）/b=1/2...