Question

①等比数列an中,an>0,若a1*a5=32,则log∨2 a1+log∨2 a2+……+log∨2 a8=?

Answer 1

1.log没有底数,没法给你解了

2. a1a2a3a4.a19a20 =a1a20a2a19a3a18.a10a11

由等比数列得a6a15=a9a12=a1a20=a2a19

所以a1a2a3a4.a19a20 =(30/2)^10=15^10

3.( 3+2√2)(3-2√2)=9-8=1=1^2

所以其等比中项为1

4.跟第2题类似.a2*a3*a4*a5*a6*a7*a8*a9=(a1a10)^4=3^4