a(n)×a(n+1)=2^n.......①
a(n+1)×a(n+2)=2^(n+1)......②
②÷①得
[a(n+1)×a(n+2)]/[a(n)×a(n+1)]=2^(n+1)/2^n
a(n+2)/a(n)=2
所以a1=1,a3=2,a5=4,a7=8,a9=16
an*a(n+1)=2^n 把n=1代入上式
a1*a2=2...
a(n)×a(n+1)=2^n.......①
a(n+1)×a(n+2)=2^(n+1)......②
②÷①得
[a(n+1)×a(n+2)]/[a(n)×a(n+1)]=2^(n+1)/2^n
a(n+2)/a(n)=2
所以a1=1,a3=2,a5=4,a7=8,a9=16
an*a(n+1)=2^n 把n=1代入上式
a1*a2=2...