Find:

10th term of the A.P. 1, 4, 7,10,.....

A.P is known for Arithmetic Progression whose common difference = an – an-1 where n > 0


a = a1 = 1, a2 = 4


Common difference, d = a2 – a1 = 4 – 1 = 3


To find the tenth term of A.P, firstly find an


We know, an = a + (n-1) d where a is first term or a1 and d is common difference


∴ an = 1 + (n-1) 3


⇒ an = 1 + 3n – 3


⇒ an = 3n – 2


When n = 10:


a10 = 3(10) – 2


⇒ a10 = 30 – 2


⇒ a10 = 28


Hence, 10th term of A.P. is 28


1