### Home > PC > Chapter 10 > Lesson 10.2.1 > Problem 10-71

10-71.

In parametric equations, the parameter, or “helping variable,” does not have to be time. In fact, you have studied parametric equations extensively in Chapter 4 without knowing it!

Use the diagram to express

in terms of.Use the diagram to express

in terms of.From parts (a) and (b) we know that the parametric equations for the unit circle are

and. Make a table foretc. up to , with three columns using ,, and.Plot the

- and-values you generated on graph paper to see the circle.Write parametric equations for the circle of radius

centered at the origin. Write parametric equations for the circle of radius

centered at .