Question

the sum of the first n natural number is​

Answer 1

Answer:

Sum of the First n Natural Numbers

We prove the formula 1+ 2+ ... + n = n(n+1) / 2, for n a natural number. There is a simple applet showing the essence of the inductive proof of this result.

Answer 2

Step-by-step explanation:

S

n

=1+2+3+....+n

S

n

=

2

n

[2a+(n−1)d] where a=1,d=2−1=1

⇒S

n

=

2

n

[2×1+(n−1)1]

⇒S

n

=

2

n

(n+1)

∴ Sum of first n natural numbers=

2

n(n+1)