| Exam Board | Edexcel |
| Module | PMT Mocks (PMT Mocks) |
| Topic | Parametric equations |
14. A curve \(C\) has parametric equations
$$x = 1 - \cos t , \quad y = 2 \cos 2 t , \quad 0 \leq t < \pi$$
a. Show that the cartesian equation of the curve can be written as \(y = k ( 1 - x ) ^ { 2 } - 2\) where \(k\) is an integer.
b. i. Sketch the curve C .
ii. Explain briefly why C does not include all points of \(y = k ( 1 - x ) ^ { 2 } - 2 , x \in \mathbb { R }\).
The line with equation \(y = k - x\), where \(k\) is a constant, intersects C at two distinct points.
(c) State the range of values of \(k\), writing your answer in set notation.