(b) We can show that the set {(x,y)∣x,y are positive integers} is countable by finding a 1-1 mapping from (x,y) to an integer. Given (1,1)→1, (1,2)→2, (1,3)→4, (1,4)→7, (2,1)→3, (2,2)→5, (2,3)→8, (3,1)→6, (3,2)→9, (4,1)→10, please find which (x,y) maps to 465? (5%)
