We often graph functions by letting one coordinate be dependent on another. For example, graphing the function has y values that we trace out dependent upon x values. However, it is very useful to graph functions by letting each coordinate be equal to an equation of an independent variable, known as a parameter. Changing the value of the parameter can change value of any coordinate being used. We generally choose a range of values that the parameter can take on, and the values that our function takes on as the parameter varies traces out a curve, known as a parametrized curve.