Question

Which of the following form an AP? Justify your answer.
1, 1, 2, 2, 3, 3,...

Answer 1

We have a₁ = 1 , a₂ = 1, a₃ = 2 and a₄ = 2

a₂ – a₁ = 0

a₃ – a₂ = 1

Clearly, the difference of successive terms is not same

Therefore given list of numbers does not form an AP.