已知f(n)=1+ 1 2 + 1 3 +L+ 1 n (n∈N * ),用数学归纳法证明f(2

2024-12-03 18:48:27
推荐回答(1个)
回答1:

因为假设n=k时,f(2 k )= 1+
1
2
+
1
3
+…+
1
2 k

当n=k+1时,f(2 k+1 )= 1+
1
2
+
1
3
+…+
1
2 k
+
1
2 k +1
+…+
1
2 k+1

∴f(2 k+1 )-f(2 k )=
1
2 k +1
+
1
2 k +2
+…+
1
2 k+1

故答案为:
1
2 k +1
+
1
2 k +2
+…+
1
2 k+1