Program to find sum of harmonic series

Harmonic series is inverse of a arithmetic progression. In general, the terms in a harmonic progression can be denoted as 1/a, 1/(a + d), 1/(a + 2d), 1/(a + 3d) .... 1/(a + nd). 
As N^th term of AP is given as ( a + (n – 1)d). Hence, N^th term of harmonic progression is reciprocal of Nth term of AP, which is 1/(a + (n – 1)d), where "a" is the 1st term of AP and "d" is a common difference.

Method #1: Simple approach 

Sum is 2.283333

Time Complexity : O(n) ,as we are traversing once in array.

Auxiliary Space : O(1) ,no extra space needed.

Method #2: Using recursion 

2.7178571428571425
2.9289682539682538

Time Complexity : O(n), as we are recursing for n times.

Auxiliary Space : O(n), due to recursive stack space, since n extra space has been taken.