Edexcel C3 2012 January — Question 7

Exam BoardEdexcel
ModuleC3 (Core Mathematics 3)
Year2012
SessionJanuary
TopicPartial Fractions
TypeFind inverse function after simplification

  1. The function f is defined by
$$\mathrm { f } : x \mapsto \frac { 3 ( x + 1 ) } { 2 x ^ { 2 } + 7 x - 4 } - \frac { 1 } { x + 4 } , \quad x \in \mathbb { R } , x > \frac { 1 } { 2 }$$
  1. Show that \(\mathrm { f } ( x ) = \frac { 1 } { 2 x - 1 }\)
  2. Find \(\mathrm { f } ^ { - 1 } ( x )\)
  3. Find the domain of \(\mathrm { f } ^ { - 1 }\) $$\mathrm { g } ( x ) = \ln ( x + 1 )$$
  4. Find the solution of \(\mathrm { fg } ( x ) = \frac { 1 } { 7 }\), giving your answer in terms of e .