已知函数f（x）＝log√2x,且数列｛f（an）｝是首项为2,公差为2的等差数列.

f(x)=log√2(x)
f(an)=log√2(an)
log√2(an)=2+2(n-1)=2n
an=2^n
a(n+1)=2^(n+1)
a(n+1)/an=2^(n+1)/2^n=2
a(n+1)/an=2
{an}是等比数列,公比=2
2)bn=an*f(an)=2^n*log√2(an)=2^n*log√2(2^n)=n*2^(n+1)
bn=n*2^(n+1)
Sn=1*2^2+2*2^3+3*2^4+...+(n-1)*2^n+n*2^(n+1)
2Sn= 1*2^3+2*2^4+.(n-2)*2^n+n*2^(n+2)
-Sn=2^2+2^3+2^4+...+2^(n+1)-n*2^(n+2)=-4(1-2^n)-n*2^(n+2)=-4-(n-1)2^(n+2)
Sn=4+(n-1)2^(n+2)