2.
$$y = \ln ( \tanh 2 x ) \quad x > 0$$
- Show that
$$\frac { \mathrm { d } y } { \mathrm {~d} x } = p \operatorname { cosech } 4 x$$
where \(p\) is a constant to be determined.
- Hence determine, in simplest form, the exact value of \(x\) for which \(\frac { \mathrm { d } y } { \mathrm {~d} x } = 1\)