Question

Write the relation in the Roster form and hence find its domain and range:

R₂ = `{("a", 1/"a")  "/"  0 < "a" ≤ 5, "a" ∈ "N"}`

Answer 1

R₂ = `{("a", 1/"a")  "/"  0 < "a" ≤ 5, "a" ∈ "N"}`

∴ a = 1, 2, 3, 4, 5

∴ `1/"a" = 1,1/2,1/3,1/4,1/5`

∴ R₂ = `{(1,1), (2,1/2), (3,1/3), (4, 1/4), (5, 1/5)}`

∴ Domain (R₂) = {a / 0 < a ≤ 5, a ∈ N}
= {1, 2, 3, 4, 5}

Range (R₂) = `{1/"a"  "/"  0 < "a" ≤ 5, "a" ∈ "N"}`

= `{1,1/2,1/3,1/4,1/5}`.