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IB Mathematics: Analysis and Approaches

Functions practice questions.

549 exam-style questions on Functions with answers and explanations. Six real samples below — the full set is free with an account.

Syllabus

Topics covered

Key terms

Definitions you need

domain and range of a function
Domain: the set of all input values (x-values) for which the function is defined. Range: the set of all output values (y-values) the function actually produces on that domain.
graph of a function y = f(x)
The set of all points (x, f(x)) in the plane, where x runs through the domain of f. Each x in the domain gives exactly one point, which is why the graph passes the vertical line test.
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Sample questions

What is the equation of the vertical asymptote of f(x) = (2x + 1)/(x − 3)?

  • x = 3
  • x = −3
  • y = 2
  • x = −1/2

Answer: x = 3

Vertical asymptotes of rational functions occur where the denominator is zero (and the numerator is not): x − 3 = 0 gives x = 3. The horizontal asymptote here would be y = 2.

The graph of y = f(2x) is obtained from y = f(x) by which single transformation?

  • horizontal stretch, scale factor 2
  • horizontal stretch, scale factor 1/2
  • vertical stretch, scale factor 2
  • vertical stretch, scale factor 1/2

Answer: horizontal stretch, scale factor 1/2

Replacing x by 2x compresses the graph horizontally: every point (a, b) maps to (a/2, b). Transformations inside the bracket act horizontally and 'in reverse'.

The graph of y = f(x − 3) is obtained from the graph of y = f(x) by a translation of

  • 3 units left
  • 3 units right
  • 3 units up
  • 3 units down

Answer: 3 units right

Changes inside the bracket act horizontally and in the opposite direction to the sign: x − 3 shifts the graph 3 units right.

The vertex of the parabola y = x² − 6x + 11 is at

  • (3, 2)
  • (−3, 2)
  • (3, −2)
  • (6, 11)

Answer: (3, 2)

Complete the square: y = (x − 3)² + 2, so the vertex is (3, 2). Check: x = −b/(2a) = 3 and y(3) = 9 − 18 + 11 = 2.

The horizontal asymptote of the graph of y = 5e⁻ˣ + 2 is

  • y = 0
  • y = 2
  • y = 5
  • y = 7

Answer: y = 2

As x → ∞, e⁻ˣ → 0, so y → 2. The “+2” shifts the natural asymptote y = 0 up to y = 2.

The gradient of the straight line through the points (1, 2) and (3, 10) is

  • 2
  • 4
  • 6
  • 8

Answer: 4

m = (10 − 2) / (3 − 1) = 8 / 2 = 4.

That was 6 of 549 Functions questions.

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549 Functions questions — free with an account. Spaced repetition, streaks and full exam simulations included.

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