Find the sum of the ‘n’ even natural numbers. Hence find the sum of the first 20 even natural numbers.
The sequence of even natural numbers is 2, 4, 6, ...
This sequence is an A.P. with a = 2, d = 4 – 2 = 2
(\therefore) The sum of the ‘n’ even natural numbers is n (n + 1) and the sum of the first 20 even natural numbers is 420.
