Sum of the first nth term of Series

Description:

Task:

Your task is to write a function which returns the sum of following series upto nth term(parameter).

Series: 1 + 1/4 + 1/7 + 1/10 + 1/13 + 1/16 +...

Rules:

• You need to round the answer to 2 decimal places and return it as String.
• If the given value is 0 then it should return 0.00
• You will only be given Natural Numbers as arguments.

Examples:(Input --> Output)

1 --> 1 --> "1.00"
2 --> 1 + 1/4 --> "1.25"
5 --> 1 + 1/4 + 1/7 + 1/10 + 1/13 --> "1.57"

 

 

Solution:

1. Find the given series of 'n'.
2. Sum the series and return to the second decimal place.

 

 

def series_sum(n):
    return '{:.2f}'.format(sum(1/(3*i+1) for i in range(n)))