Question

write the first four terms of the following sequence an= 2n^2+1​

Answer 1

Answer: 3,9,15,21...

an = 2n² + 1

a₁ = 2(1)² + 1 = 2 + 1= 3

a₂ = 2(2)²+1 = 8+1 = 9

here a = 3, d = a₂-a₁ = 9-3 = 6.

a₃ = a+2d = 3+2(6) = 15

a₄ = a+3d = 3+3(6) = 21

hence, first four terms =3,9,15,21...

Step-by-step explanation: