Edexcel Paper 1 2024 June — Question 8

Exam BoardEdexcel
ModulePaper 1 (Paper 1)
Year2024
SessionJune
TopicComposite & Inverse Functions

  1. The functions f and g are defined by
$$\begin{array} { l l } f ( x ) = 4 - 3 x ^ { 2 } & x \in \mathbb { R }
g ( x ) = \frac { 5 } { 2 x - 9 } & x \in \mathbb { R } , x \neq \frac { 9 } { 2 } \end{array}$$
  1. Find fg(2)
  2. Find \(\mathrm { g } ^ { - 1 }\)
    1. Find \(\mathrm { gf } ( x )\), giving your answer as a simplified fraction.
    2. Deduce the range of \(\operatorname { gf } ( x )\). The function h is defined by $$h ( x ) = 2 x ^ { 2 } - 6 x + k \quad x \in \mathbb { R }$$ where \(k\) is a constant.
  3. Find the range of values of \(k\) for which the equation $$\mathrm { f } ( x ) = \mathrm { h } ( x )$$ has no real solutions.