Which of the following are APs? If they form an AP, find the common difference d and write three more terms.

a, a2, a3, a4


For a series to be in AP, the common difference (d) should be

Equal.


D1 = second term – first term = a2 - a = a2 - a


D2 = Third term - Second term = a3 - a2 = a3 - a2


Since common difference is not equal the above series is not in AP


4
1