Question

Select the correct answer from given alternatives.

If f : R → R is defined by f(x) = x³ then f^–1 (8) is equal to :

Options

• {2}

• {–2, 2}

• {–2}

• (–2, 2)

Answer 1

{2}

Explanation;

f(x) = x³ = y, say

∴ x = `y^(1/3)` = f^–1 (y)

∴ f^–1 (8) = `(8)^(1/3) = (2^3)^(1/3)`

∴ f^–1 (8) = {2}