Mathematicians love parametric equations!
When the coordinates of a function are expressed in terms of a third independent variable, parametric equations are produced. E.g. x = 3 sin (t) | y = 3 cos (t) - t is the parameter sin t = x/3 => sin 2 t = x 2 /9 cos t = y/3 => cos 2 t = y 2 /9 x 2 + y 2 = 9 x 2 + y 2 = 3 2 This is a circle with radius 3 with the centre being at the origin. The above parametric equations produce a circle. For more in-depth knowledge on parametric equations, please follow the this link and learn interactively. In order to practice the above heart interactively using parametric equations, please use the following simulation: