The nth term of the AP a,3a,5a,is:
(2)
Given AP is a,3a,5a,… where first term =a and d=3a-a=2a.
∴Its nthterm,an=a+(n-1)d=a+(n-1)×2a⇒an=a+2an-2a=2an-a=a(2n-1)