如果数列an满足a1,a2/a1,a3/a2,...,an/an-1是首项为1,公比为2的等比数列,则a6=
问题描述:
如果数列an满足a1,a2/a1,a3/a2,...,an/an-1是首项为1,公比为2的等比数列,则a6=
答
a1是1,a2是2,,,,一个个往后推
答
a6/a5* a5/a4 *...*a2/a1 *a1
=2^5 *2^4 *2^3 *2^2 *2^1 *2^0
=2^(5+4+3+2+1)
=2^15
a6=2^15
答
an/a(n-1)=1×2^(n-1)=2^(n-1)a(n-1)/a(n-2)=2^(n-2)…………a2/a1=2连乘an/a1=2×2²×...×2^(n-1)=2^[1+2+...+(n-1)]=2^[n(n-1)/2]an=a1×2^[n(n-1)/2]=1×2^[n(n-1)/2]=2^[n(n-1)/2]a6=2^(6×5/2)=2^15=3276...