IGCSE Mathematics Extended E2.13.3 Form composite functions as defined by gf(x) = g(f(x)) Question Bank

• Form composite functions as defined by gf(x) = g(f(x)). Examples include: • f (x) = 3x – 5 • g(x) = 3(x + 4) • h(x) = 2x2 + 3. e.g. f(x) = 3 x + 2 and g(x) = (3x + 5)2. Find fg(x). Give your answer as a fraction in its simplest form. Candidates are not expected to find the domains and ranges of composite functions. This topic may include mapping diagrams.