Write the sum of first n odd natural numbers.
First n odd numbers are 1, 3, 5, 7, 9........., (2n–1) which forms an A.P
a= 1
l= 2n – 1 where l be the last term
Sn = 
(2a + (n–1) d) or 
(a + l)
= 
(1 + 2n –1)
= 
(2n)
=n (n)
=n2
8
Write the sum of first n odd natural numbers.
First n odd numbers are 1, 3, 5, 7, 9........., (2n–1) which forms an A.P
a= 1
l= 2n – 1 where l be the last term
Sn = (2a + (n–1) d) or (a + l)
= (1 + 2n –1)
= (2n)
=n (n)
=n2