We are given the function f:R -> R defined as follows,

f(x) = 1/n, if x is a rational number

f(x) = 0, if x is irrational

(a) first I need to find a sequence f_n of cont. functions such that f_n(x) -> f(x) as x -> infinity

(b) second I need to prove that f is continuous at each irrational point and discontinuous at each rational point.

help?