No.47

Key Definitions:

• Parameter - The third variable (usually t or Θ).
• t represents time; Θ represents angle
• Parametric Equation - An equation that equates x or y to the third variable (ex: y=2t)
• Plane Curve - An interval in which both x and y are continuous functions of t. Often represented by C.

Main Purpose - to give a more realistic illustration of a graph by including the time or angle at which any given point occurs.

Steps to Solving Parametric Equations:

1. Eliminate the parameter to find a rectangular equation
2. Sketch the graph of basic x,y equation once parameter is eliminated.
3. Use parametric equations to find (x,y) at point t.
1. Usually use t = -2,-1,0,1,2.

Credit by Joe Laski