Question

in an AP if an=2n+1 then common difference is?

Answer 1

an = 2n + 1

___________

Put n = 1

⇒a1 = 2(1) + 1

⇒a1 = 2 + 1

⇒a1 = 3

Put n = 2

⇒a2 = 2(2) +1

⇒a2 = 4 + 1

⇒a2 = 5

⇒d = a2 - a1

⇒d = 5 - 3

⇒d = 2

Answer 2

aₙ = 2n + 1

Putting n=1,

a₁ = 2 + 1

    = 3

Putting n=2,

a₂ = 4 + 1

     = 5

Thus Common difference = a₂ - a₁  

d = 3 - 1

d = 2