Edexcel C3 2014 January — Question 8

Exam BoardEdexcel
ModuleC3 (Core Mathematics 3)
Year2014
SessionJanuary
TopicComposite & Inverse Functions

8. The function \(f\) is defined by $$\mathrm { f } : x \rightarrow 3 - 2 \mathrm { e } ^ { - x } , \quad x \in \mathbb { R }$$
  1. Find the inverse function, \(\mathrm { f } ^ { - 1 } ( x )\) and give its domain.
  2. Solve the equation \(\mathrm { f } ^ { - 1 } ( x ) = \ln x\). The equation \(\mathrm { f } ( t ) = k \mathrm { e } ^ { t }\), where \(k\) is a positive constant, has exactly one real solution.
  3. Find the value of \(k\).