4 The parametric equations of a curve are
$$x = t + \cos t , \quad y = \ln ( 1 + \sin t )$$
where \(- \frac { 1 } { 2 } \pi < t < \frac { 1 } { 2 } \pi\).
- Show that \(\frac { \mathrm { d } y } { \mathrm {~d} x } = \sec t\).
- Hence find the \(x\)-coordinates of the points on the curve at which the gradient is equal to 3 . Give your answers correct to 3 significant figures.