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Python Program for Sum of squares of first n natural numbers
In this article, we will learn about the solution and approach to solve the given problem statement.
Problem statement
Given a positive integer N as input . We need to compute the value of 12 + 22 + 32 + ….. + N2.
Problem statement:This can be solved by two methods
- Multiplication addition arithmetic
- Using mathematical formula
Approach 1: Multiplication & Addition Arithmetic
Here we run a loop from 1 to n and for each i, 1 <= i <= n, find i2 and add to sm.
Example
def sqsum(n) : sm = 0 for i in range(1, n+1) : sm = sm + pow(i,2) return sm # main n = 5 print(sqsum(n))
Output
55
Approach 2: By using mathematical formulae
As we all know that the sum of squares of natural numbers is given by the formula −
(n * (n + 1) * (2 * n + 1)) // 6n * (n + 1) * (2 * n + 1)) // 6 (n * (n + 1) * (2 * n + 1)) // 6(n * (n + 1) * (2 * n + 1)) // 6
Example
def squaresum(n) : return (n * (n + 1) * (2 * n + 1)) // 6 # Driven Program n = 10 print(squaresum(n))
Output
385
Conclusion
In this article, we learned about the approach to find the Sum of squares of first n natural numbers.
Updated on: 26-Sep-2019
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