Functions (one-one, onto, inverse)

Grade 12 Maths — Functions (one-one, onto, inverse): 25 practice questions with instant scoring and explanations.

1. A function f: A → B is one-one (injective) if:
2. A function f: A → B is onto (surjective) if:
3. A function that is both one-one and onto is called:
4. For a function to have an inverse, it must be:
5. If f(x) = 2x + 3, then f is:
6. The inverse of f(x) = 2x - 5 is:
7. If f(x) = x², then f is:
8. For which of the following does an inverse function exist?
9. If f: {1, 2, 3} → {a, b, c, d} is one-one, then:
10. The function f(x) = eˣ from ℝ to ℝ⁺ is:
11. If f⁻¹ exists, then f⁻¹(f(x)) equals:
12. The inverse of f(x) = 1/x (x ≠ 0) is:
13. A function f: A → B is NOT onto if:
14. If f: ℕ → ℕ where f(n) = n + 1, then f is:
15. The function f(x) = cos(x) on [0, π] is:
16. If f is bijective, then (f⁻¹)⁻¹ equals:
17. The inverse of f(x) = √x (x ≥ 0) is:
18. A function f: {a, b, c} → {1, 2, 3} is onto if and only if:
19. If f(x) = aˣ where a > 0, a ≠ 1, then f is:
20. The number of one-one functions from a set with 3 elements to a set with 5 elements is:
21. If f and g are bijective functions, then (f ∘ g)⁻¹ equals:
22. A function f is injective if and only if it is:
23. The inverse of f(x) = ln(x) (x > 0) is:
24. If f: A → B and |A| = 5, |B| = 3, then f can be:
25. The function f(x) = |x| on ℝ is: