CAIE IGCSE Additional Math 1 functions
Use this Functions hub to move from terminology and notation into domains, ranges, inverse functions, composite functions and graph sketches.
- Syllabus
- 2028–2030
- Course
- Additional Mathematics 0606
Use this Functions hub to move from terminology and notation into domains, ranges, inverse functions, composite functions and graph sketches.

The diagram shows the graph of f(x)=acosbx+c, for 0⩽x⩽38π radians.
Explain why f is a function.
For each value of x in the domain there is exactly one value of f(x). B1
Write down the range of f.
−5⩽f(x)⩽1
B1
Describe the relationship between the graph of f(x) and the graph of f−1(x).
Reflection in y=x oe
B1
A function g is defined by g(x)=ex−2 for x⩾2.
Find an expression for g−1(x).
Complete method including change of subject and swap of variables at some point.
M2; M1 for lny=x−2 or lnx=y−2 soi
g−1(x)=(lnx)2+2
A1 Final answer
Write down the range of g−1.
g−1(x)⩾2
B1
A function h is defined by h(x)=x21+2 for x>0.
Find an expression for gh(x) in its simplest form.
e1/x or xe or ex−1
B2 Final answer
B1 for ex21+2−2 soi oe

B1 for each one correct entry; 5 marks total.
It is given that h(x)=(x−1)2+3 for x⩾a. The value of a is as small as possible such that h−1 exists.
Write down the value of a.
a=1
B1
Write down the range of h.
h(x)⩾3
B1
Find h−1(x) and state its domain.
x=(y−1)2+3y=1+x−3
M1
h−1(x)=1+x−3
A1
Domain: x⩾3. B1