13. The curve \(C\) has polar equation \(r = 2 - \cos \theta\) for \(0 \leqslant \theta \leqslant 2 \pi\).
- Sketch the curve \(C\).
- Show that the values of \(\theta\) at which the tangent to the curve \(r = 2 - \cos \theta\) is parallel to the initial line satisfy the equation
$$2 \cos ^ { 2 } \theta - 2 \cos \theta - 1 = 0$$
- Find the polar coordinates of the points where the tangent to the curve \(r = 2 - \cos \theta\) is parallel to the initial line.