Question

Find the nth term and then sum of n terms of 1+3+6+10.........

Answer 1

Answer:

here

a = 1

d = 2

Sn = n/2 x (2a + (n-1)(d))

put the values

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

Sn = 2.n/2 x (1 + n-1)

Sn = n(n)

Sn = n²

hope this will help you

Answer 2

Answer:

Sn=n^2. ....................