The sum of n terms of a series is

Question

2+6+10+.....is ?

Answer 1

The series 2 , 6, 10,...

Common difference d = t₂ - t₁  = 6 - 2 = 4

a = 2

Formula for sum of n terms in arithmetic sequence Sn = n/2 [2a + (n -1)d]

Sn = n/2 [ 2(2) + (n - 1) 4]

= n/2 [ 4 + 4n - 4]

= n/2 (4n)

= 2n²

Sum of n terms = 2n².