lim 2^n/2^(n+1)+a^n=0 实数a的取值范围?2)若a>0 lim 3^n-a^n / 3^(n+1)+a^(n+1)=

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lim 2^n/2^(n+1)+a^n=0 实数a的取值范围?2)若a>0 lim 3^n-a^n / 3^(n+1)+a^(n+1)=

lim 2^n/2^(n+1)+a^n=0 实数a的取值范围?2)若a>0 lim 3^n-a^n / 3^(n+1)+a^(n+1)=
lim 2^n/2^(n+1)+a^n=0 实数a的取值范围?
2)若a>0 lim 3^n-a^n / 3^(n+1)+a^(n+1)=

lim 2^n/2^(n+1)+a^n=0 实数a的取值范围?2)若a>0 lim 3^n-a^n / 3^(n+1)+a^(n+1)=
1、lim 2^n/[2^(n+1)+a^n]
=lim1/[2+(a/2)^n]
=0
所以2+(a/2)^n=∞
即(a/2)^2>1
a>2或a3时,有3/a