题目内容
设函数f(x)满足2f(n+1)=2f(n)+n,f(1)=2,则f(5)=( )
A.6 | B.6.5 | C.7 | D.7.5 |
∵函数f(x)满足2f(n+1)=2f(n)+n,f(1)=2,
∴f(2)=f(1)+
=1+
=
,
f(3)=f(2)+1=
+1=
,
f(4)=f(3)+
=
+
=4,
f(5)=f(4)+2=4+2=6.
故选:A.
∴f(2)=f(1)+
1 |
2 |
1 |
2 |
3 |
2 |
f(3)=f(2)+1=
3 |
2 |
5 |
2 |
f(4)=f(3)+
3 |
2 |
5 |
2 |
3 |
2 |
f(5)=f(4)+2=4+2=6.
故选:A.
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