Question

find the sum of first n natural numbers​

Answer 1

Answer:

n(n+1) ÷2

Explanation:

for even numbers

there is n(n+1)

Answer 2

A. P formed by first n natural numbers will be: 1,2,3,4...................n

In this A. P.

First term, a = 1

Common difference, d = 1

Taking no. Of terms = n

Sn =( n/2)×(2a + (n-1) d)

(Putting values)

Sn = (n/2)×(2(1) + (n-1) (1))

Sn = (n/2)× (2+n-1)

Sn= (n/2) (n+1)

Sn= (n^2 +n) /2

So the sum of first n natural numbers will be (n^2+n) /2.