Find tn of the A.P.: 3, 6, 9, ....

Answer:

For an A.P. tn  = a + ( n – 1 ) d

Here, a  = 3,  d = t2 – t1 = 6 – 3 = 3

∴ tn = 3 + (n – 1)3

∴ tn = 3 + 3n  - 3

∴ tn = 3n