Unit 2: Functions

Topic 2.5: Composite and Inverse Functions Questions

Practice 16 exam-style questions for IB Math AA SL Topic 2.5. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.

1Find2 marks
2026Aimnova practice — 2.5.1
f(x) = 3x − 2 and g(x) = x + 4. Find (f∘g)(2).
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2Find2 marks
2026Aimnova practice — 2.5.1
f(x) = x² and g(x) = 2x − 1. Find (g∘f)(3).
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3Find2 marks
2026Aimnova practice — 2.5.2
Find the inverse of f(x) = 5x − 2, giving your answer as f⁻¹(x).
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4Find2 marks
2026Aimnova practice — 2.5.1
f(x) = 2x + 3 and g(x) = x². Find an expression for (f∘g)(x).
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5Solve3 marks
2026Aimnova practice — 2.5.1
f(x) = 4x − 1 and g(x) = x + 2. Solve (f∘g)(x) = 19.
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6Find3 marks
2026Aimnova practice — 2.5.1
f(x) = x + 1 and g(x) = 2x.
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7Show2 marks
2026Aimnova practice — 2.5.2
Show that f⁻¹(x) = (x − 1)/2 is the inverse of f(x) = 2x + 1 by composing the two functions.
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8Find2 marks
2026Aimnova practice — 2.5.1
f(x) = x − 5 and g(x) = x². Find an expression for (g∘f)(x).
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9Find2 marks
2026Aimnova practice — 2.5.1
Functions are defined by f(x) = ln x (x > 0) and g(x) = x² + 1. Find an expression for (f∘g)(x).
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10Find3 marks
2026Aimnova practice — 2.5.2
The function f(x) = x² is defined for x ≥ 0. (a) Find f⁻¹(x). (b) State the domain of f⁻¹.
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11Find2 marks
2026Aimnova practice — 2.5.2
Find the inverse of f(x) = (x + 4)/3.
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12Find3 marks
2026Aimnova practice — 2.5.2
Find the inverse of f(x) = 3x + 7, and hence find f⁻¹(1).
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13Find2 marks
2026Aimnova practice — 2.5.2
Find the inverse of f(x) = (x/2) − 3.
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14Find3 marks
2026Aimnova practice — 2.5.1
g(x) = x². Find the linear function f(x) = ax + b such that (f∘g)(x) = 5x² + 1.
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15Find4 marks
2026Aimnova practice — 2.5.2
A function is defined by f(x) = (5 − 2x)/(x + 1).
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16Find4 marks
2026Aimnova practice — 2.5.2
Find the inverse of f(x) = (2x + 1)/(x − 3).
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