A-Level Maths Edexcel (9MA0)

Understand and use the parametric equations of curves and conversion between Cartesian and parametric forms.

For example:

• $x = 3\cos{t}$, $y = 3\sin{t}$ describes a circle centre $O$ radius $3$
• $x = 2 + 5\cos{t}$, $y = -4 + 5\sin{t}$ describes a circle centre $(2, -4)$ with radius $5$
• $x = 5t$, $y = \frac{5}{t}$ describes the curve $xy = 25$ (or $y = \frac{25}{x}$)
• $x = 5t$, $y = 3t^2$ describes the quadratic curve $25y = 3x^2$ and other familiar curves covered in the specification.

Students should pay particular attention to the domain of the parameter $t$, as a specific section of a curve may be described.