Parametric equations 1: Parametric curves

Question 1

Describe parametric equations

Answer 1

• In parametric equations, x and y are given in terms of a third variable.
• the parameter usually t or θ

Question 2

How to rewrite parametric equations in cartesian form

Answer 2

• by eliminating the parameter algebraically
• by using a trig identity

Question 3

Parametric circles

Answer 3

unit circle is given by x = cosθ and y = sinθ
parametric equations of a circle centre (a, b) radius r are:
x = a + rcosθ y = b + rsinθ