Check whether the following sequences are in A.P. (iii) 9, 13, 17, 21, 25,...

Check whether the following sequences are in A.P.

(iii) 9, 13, 17, 21, 25,...

Solution :

d = t2 - t1 d = 13 - 9 d  = 4

d = t3 - t2 d = 17 - 13 d  = 4

The given sequence is an arithmetic progression.