Question

which of the following is the sum the first or natural number (6,1/6,30,3)​

Answer 1

Answer:  The natural numbers are 1,2,3,4,... so sum of first n natural numbers as

1 + 2 + 3 + 4 + ... + n

Sn = 1 + 2 + 3 + 4 + ... + n

As we know that

Sn=

n

2

 

[2a+(n−1)d]

According to 'n' natural numbers

first term = a = 1 and common difference = d = 1

∴ Sn=

n

2

 

[2×1+(n−1)×1]

Sn=

n

2

 

[2+n−1]

Sn=

n

2