Question

Answer the following:

Find the domain of the following function.

f(x) = ^5–xP_x–1

Answer 1

f(x) = ^5–xP_x–1 

ⁿP_r is defined if n ∈ N, r ∈ Wand r ≤ n

∴ x – 1 ≤ 5 – x

∴ 2x ≤ 6

∴ x ≤ 3

For x ∈ W and x ≤ 3, x = 0, 1, 2, 3

But if x = 0, x – 1 = – 1 < 0

∴ x ≠ 0

∴ x = 1, 2, 3

∴ the solution set is {1, 2, 3}.