8 It is given that \(\mathrm { f } ( x ) = 2 \sinh x + 3 \cosh x\).
- Show that the curve \(y = \mathrm { f } ( x )\) has a stationary point at \(x = - \frac { 1 } { 2 } \ln 5\) and find the value of \(y\) at this point.
- Solve the equation \(\mathrm { f } ( x ) = 5\), giving your answers exactly.
\section*{Question 9 begins on page 4.}