f(x)满足f(x+y)=f(x)×f(y),且f(1)=0.5.
f(x)满足f(x+y)=f(x)×f(y),且f(1)=0.5.
f(x)满足f(x+y)=f(x)×f(y),且f(1)=0.5.
1,当n∈N,求f(n)的表达式
2,设an=×f(n),n∈N,求证:a1+a2+a3+.+an<2
3设bn=n×f(n+1)/f(n),n∈N,Sn为{bn}的前n项和,求1/S1+1/S2+...+1/Sn.
2,设an=n×f(n),n∈N,求证:a1+a2+a3+.....+an<2