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