Question

If the domain of function f(a) = a² - 4a + 8 is (-∞, ∞), then the range of function is ______

Options

• (2, ∞)

• (4, ∞)

• (4, ∞)

• (-∞, -2)

Answer 1

If the domain of function f(a) = a² - 4a + 8 is (-∞, ∞), then the range of function is (4, ∞).

Explanation:

a² - 4a + 8 = (x - 2)² + 4

Here, the minimum value is 4 and the maximum ∞. Hence, the range of a function is (4, ∞).