等比数列a+log(2)3,a+log(4)3,a+log(8)3
问题描述：
等比数列a+log(2)3,a+log(4)3,a+log(8)3
求公比q.
答
[a+log(4)3]^2=[a+log(2)3][a+log(8)3][a+lg3/2lg2]^2=[a+lg3/lg2][a+lg3/3lg2]令x=lg3/(6lg2)则(a+3x)^2=(a+6x)(a+2x)a^2+6ax+9x^2=a^2+8ax+12x^2-3x^2=2ax显然x不等于0所以a=-3x/2所以q=(a+3x)/(a+6x)=(-3x/2+3x)/...