Question

The domain of the function f(x) = 21- xC3x - 1 + 25 - 3xP5x - 3 is

(a) {1, 2, 3}

(b) {2, 3}

(c) {2, 3, 4}

(d) {2, 3, 4, 5}

Answer 1

The correct option (a) {1, 2, 3}

Explanation:

21 – x > 0, 3x – 1 ≥ 0, 21 – x ≥ 3x – 1 and 25 – 3x > 0, 5x – 3 ≥ 0, 25 – 3x ≥ 5x – 3

⇒ 3/5 < x ≤ 7/2

Hence domain of f = {1, 2, 3}